Thermosyphon

ABSTRACT

A thermosiphon applied to a moving body includes a condenser and a plurality of coolers. Each of the plurality of coolers includes a first flow channel forming member, a second flow channel forming member, and a third flow channel forming member. The second flow channel forming member defines a refrigerant inlet that is located below a center portion of a supply flow channel defined by the first flow channel forming member in a vertical direction. The plurality of coolers are arranged along a traveling direction of the moving body and the supply flow channel is fluidly connected in series with each other.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of international Patent Application No. PCT/JP2018/020960 filed on May 31, 2018, which designated the U.S. and claims the benefit of priority from Japanese Patent Application No. 2017-118870 filed on Jun. 16, 2017. The entire disclosure of the above application is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a thermosiphon.

BACKGROUND ART

A thermosiphon includes a cooler for evaporating a liquid-phase refrigerant by heat exchange between the liquid-phase refrigerant and a battery to cool the battery, and a condenser for condensing a gas-phase refrigerant from the cooler, and configures a refrigerant circuit for circulating the refrigerant between the cooler and the condenser.

SUMMARY OF THE INVENTION

In one aspect of the present disclosure, a thermosiphon applied to a moving body includes a condenser condensing a gas-phase refrigerant and discharging a liquid-phase refrigerant, and a plurality of coolers that evaporate the liquid-phase refrigerant from the condenser, the refrigerant circulating between the condenser and the plurality of coolers. Each of the plurality of coolers includes a first flow channel forming member that defines a supply flow channel through which the liquid-phase refrigerant from the condenser flows, a second flow channel forming member that defines a refrigerant inlet in communication with the supply flow channel, the second flow channel forming member extending upward from the refrigerant inlet to define an evaporation flow channel in which the liquid-phase refrigerant evaporates through heat exchange between an object to be cooled and the liquid-phase refrigerant flowing into the evaporation flow channel from the supply flow channel through the refrigerant inlet and generates the gas-phase refrigerant. and a third flow channel forming member that defines a discharge flow channel through which the gas-phase refrigerant from the evaporation flow channel flows toward the condenser. The refrigerant inlet is located below a center portion of the supply flow channel in a vertical direction. The plurality of coolers are arranged along a traveling direction of the moving body and the supply flow channel of each of the plurality of coolers is fluidly connected in series with each other so that the liquid-phase refrigerant is sequentially supplied to the supply flow channel of each of the plurality of coolers.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings.

FIG. 1 is a diagram showing a battery cooling unit mounted on a vehicle according to a first embodiment, which is a diagram showing a state in which the vehicle is inclined.

FIG. 2 is a schematic diagram showing a general configuration of the battery cooling unit of FIG. 1.

FIG. 3 is a schematic diagram showing an appearance of a cooler and a secondary battery of FIG. 1.

FIG. 4 is an exploded view of the cooler and the secondary battery of FIG. 1.

FIG. 5 is a diagram showing an internal structure of an evaporator of FIG. 4.

FIG. 6 is a perspective view showing the internal structure of the evaporator of FIG. 4.

FIG. 7 is a front view A of the evaporator of FIG. 4 and a cross-sectional view B of the evaporator.

FIG. 8 is a front view B of the evaporator of FIG. 4 and a cross-sectional view A of the evaporator.

FIG. 9 is a perspective view showing an internal structure of the cooler of FIG. 1.

FIG. 10 is a schematic diagram showing a refrigerant flow inside the cooler of FIG. 1.

FIG. 11 is a schematic diagram showing a refrigerant flow in the cooler of FIG. 1 at the time of inclination.

FIG. 12 is a schematic view showing the refrigerant flow in the cooler of FIG. 1 at the time of inclination.

FIG. 13A is a schematic diagram showing a refrigerant flow in the cooler in a comparative example.

FIG. 13B is a schematic diagram showing the refrigerant flow in the cooler in the comparative example.

FIG. 14 is a diagram showing a battery cooling unit mounted on a vehicle according to a second embodiment, which is a diagram showing a state in which the vehicle is inclined.

FIG. 15 is a schematic diagram showing a general configuration of the battery cooling unit of FIG. 14.

FIG. 16 is a schematic diagram showing a refrigerant flow inside the cooler of FIG. 14.

FIG. 17 is a diagram showing an internal structure of an evaporator of FIG. 14.

FIG. 18A is a diagram showing a battery cooling structure of the battery cooling unit according to the third embodiment.

FIG. 18B is a diagram showing a battery cooling structure of the battery cooling unit according to the third embodiment.

FIG. 19A is a diagram showing an internal structure of an on-off valve of the battery cooling unit according to the third embodiment.

FIG. 19B is a diagram showing the internal structure of the on-off valve of the battery cooling unit according to the third embodiment.

FIG. 20A is a diagram showing a battery cooling structure of a battery cooling unit according to a fourth embodiment.

FIG. 20B is a diagram showing the battery cooling structure of the battery cooling unit according to the fourth embodiment.

FIG. 21 is a diagram showing an overall configuration of a battery cooling unit according to a fifth embodiment.

FIG. 22 is a flowchart showing a refrigerant control process of an electronic control device according to the fifth embodiment.

FIG. 23 is an exploded view of a cooler according to a sixth embodiment.

FIG. 24A is a diagram showing an internal structure of the cooler in FIG. 23.

FIG. 24B is a cross-sectional view taken along a line XXIVB-XXIVB in FIG. 24A.

FIG. 24C is a cross-sectional view taken along a line XXIVC-XXIVC in FIG. 24A.

FIG. 25A is a diagram showing an internal structure of a cooler according to a seventh embodiment.

FIG. 25B is a cross-sectional view taken along a line XXVB-XXVB in FIG. 25A.

FIG. 25C is a cross-sectional view taken along a line XXVC-XXVC in FIG. 25A.

FIG. 26A is a diagram showing an internal structure of a cooler according to an eighth embodiment.

FIG. 26B is a cross-sectional view taken along a line XXVIB-XXVIB in FIG. 26A.

FIG. 26C is a cross-sectional view taken along a line XXVIC-XXVIC in FIG. 26A.

FIG. 27A is a diagram showing an internal structure of a cooler in a comparative example.

FIG. 27B is a cross-sectional view taken along a line XXVIIB-XXVIIB in FIG. 27A.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure will be described below with reference to the drawings. In the drawings, the same reference numerals are assigned to the same or equivalent parts in the following embodiments in order to simplify the description.

The present inventors have examined a vehicle thermosiphon in which a battery mounted on an automobile is cooled by a cooler.

As shown in FIGS. 27A and 27B, a cooler 2, as a comparative example, includes a refrigerant supply flow channel 2 a to which a liquid-phase refrigerant from a condenser is supplied, an evaporation flow channel portion 2 b for evaporating the liquid-phase refrigerant by exchanging a heat between the liquid-phase refrigerant from the refrigerant supply flow channel 2 a and the battery, and a refrigerant discharge flow channel 2 c for guiding a gas-phase refrigerant from the evaporation flow channel portion 2 b to the condenser (refer to FIGS. 27A and 27B).

In this example, when the automobile climbs an uphill, a front side of the automobile in a vehicle traveling direction is positioned above a rear side in the vehicle traveling direction. For that reason, the cooler 2 assumes a more inclined posture than a specified posture (hereinafter referred to as a reference posture).

In that case, the refrigerant collects in the lowest part of a refrigerant circuit of the thermosiphon under an influence of gravity. For that reason, the liquid-phase refrigerant in the refrigerant supply flow channel 2 a of the cooler may be reduced.

Therefore, when a refrigerant inlet of the evaporation flow channel portion 2 b is disposed on an upper side of the refrigerant supply flow channel 2 a, a liquid surface of the liquid-phase refrigerant may be located on the lower side of the refrigerant inlet of the evaporation flow channel portion 2 b in the refrigerant supply flow channel 2 a.

For that reason, the supply of the liquid-phase refrigerant from the refrigerant supply flow channel 2 a to the evaporation flow channel portion 2 b becomes unstable, and the cooling of the battery (that is, a target to be cooled) becomes unstable.

It is an objective of the present disclosure to provide a cooler and a thermosiphon which stabilize cooling of an object to be cooled.

In one aspect of the present disclosure, a cooler forms, together with a condenser, a thermosiphon that circulates a refrigerant therethrough, the condenser condensing a gas-phase refrigerant and discharging a liquid-phase refrigerant. The cooler includes:

a first flow channel forming member that defines a supply flow channel through which the liquid-phase refrigerant from the condenser flows;

a second flow channel forming member that defines a refrigerant inlet in communication with the supply flow channel, the second flow channel forming member extending upward from the refrigerant inlet to define an evaporation flow channel in which the liquid-phase refrigerant evaporates through heat exchange between an object to be cooled and the liquid-phase refrigerant flowing into the evaporation flow channel from the supply flow channel through the refrigerant inlet and generates the gas-phase refrigerant; and

a third flow channel forming member that defines a discharge flow channel through which the gas-phase refrigerant from the evaporation flow channel flows toward the condenser, wherein

the refrigerant inlet is located below a center portion of the supply flow channel in a vertical direction.

Therefore, even if the cooler is angled relative to a specified posture and the supply amount of the liquid-phase refrigerant from the condenser to the cooler is small, it is advantageous to dispose the liquid surface of the liquid-phase refrigerant above the refrigerant inlet as compared with when the refrigerant inlet is positioned above the center portion of the supply flow channel in the vertical direction.

As a result, the liquid-phase refrigerant can be stably supplied from the supply flow channel to the evaporation flow channel. For that reason, cooling of the target to be cooled can be stabilized.

However, when the uppermost position of the supply flow channel in a vertical direction is defined as an uppermost position and the lowermost position of the supply flow channel in the vertical direction is defined as a lowermost position, the center portion of the supply flow channel in the vertical direction means a middle position between the uppermost position and the lowermost position.

In another aspect of the present disclosure, a cooler that forms, together with a condenser, a thermosiphon that circulates a refrigerant therethrough, the condenser condensing a gas-phase refrigerant and discharging a liquid-phase refrigerant. The cooler includes:

a first flow channel forming member that defines a supply flow channel through which the liquid-phase refrigerant from the condenser flows;

a second flow channel forming member that defines a refrigerant inlet into which the liquid-phase refrigerant from the supply flow channel flows, the second flow channel forming member defining an evaporation flow channel in which the liquid-phase refrigerant evaporates through heat exchange between an object to be cooled and the liquid-phase refrigerant flowing into the evaporation flow channel through the refrigerant inlet and through which the gas-phase refrigerant flows toward the condenser;

a third flow channel forming member that defines a discharge flow channel through which the gas-phase refrigerant from the evaporation flow channel flows toward the condenser; and

at least one liquid storage that is recessed downward from the supply flow channel to store the liquid-phase refrigerant from the supply flow channel, wherein

the refrigerant inlet is in communication with the at least one liquid storage, and

the refrigerant inlet is located at the same height as a liquid surface of the liquid-phase refrigerant in the at least one liquid storage or is located below the liquid surface.

Therefore, even if the cooler is angled relative to a specified posture and the supply amount of the liquid-phase refrigerant from the condenser to the cooler is small, it is advantageous to dispose the liquid surface of the liquid-phase refrigerant above the refrigerant inlet as compared with when the refrigerant inlet is positioned above the center portion of the supply flow channel in the vertical direction.

As a result, the liquid-phase refrigerant can be stably supplied from the supply flow channel to the evaporation flow channel. For that reason, cooling of the target to be cooled can be stabilized.

In yet another aspect of the present disclosure, a thermosiphon includes:

a condenser that condenses a gas-phase refrigerant and discharges a liquid-phase refrigerant; and

a cooler that evaporates the liquid-phase refrigerant through heat exchange between an object to be cooled and the liquid-phase refrigerant flowing into the cooler from the condenser and discharges the gas-phase refrigerant to the condenser, the refrigerant circulating between the condenser and the cooler, wherein

the thermosiphon further comprises:

-   -   a determination unit that determines whether the cooler is         angled with respect to a specified posture; and     -   a refrigerant increasing unit that, upon determining by the         determination unit that the cooler is angled with respect to the         specified posture, increases a refrigerant amount of the         liquid-phase refrigerant supplied from the condenser to the         cooler as compared with when the determination unit determines         that the cooler is not angled with respect to the specified         posture.

Therefore, when the cooler is angled relative to the specified posture, by increasing the supply amount of the liquid-phase refrigerant from the condenser to the cooler, the liquid-phase refrigerant can be stably supplied to the evaporation flow channel. For that reason, cooling of the target to be cooled can be stabilized.

First Embodiment

A battery cooling unit 10 according to the present embodiment shown in FIG. 1 is mounted in an electric vehicle such as an electric vehicle or a hybrid vehicle. In the present embodiment, the battery cooling unit 10 cools secondary batteries 12 a and 12 b mounted on the electric vehicle. In other words, the secondary batteries 12 a and 12 b are to be cooled by the battery cooling unit 10.

In the electric vehicle (hereinafter, also referred to simply as a “vehicle”) equipped with the battery cooling unit 10, an electric power stored in an electric storage device (in other words, a battery pack) including the secondary batteries 12 a and 12 b as components is supplied to an electric motor through an inverter circuit or the like, whereby the vehicle travels. The secondary batteries 12 a and 12 b generate self-heat generation when outputting the electric power to the electric motor through the inverter.

When the temperature of the secondary batteries 12 a and 12 b becomes excessively high, the deterioration of battery cells 13 configuring the secondary batteries 12 a and 12 b is accelerated, and therefore, there is a need to limit the output and input of the battery cells 13 so that the self-heat generation is reduced.

For that reason, in order to secure the output and input of the battery cells 13, a cooling device for maintaining the secondary batteries 12 a and 12 b at a predetermined temperature or lower is required.

In addition, the battery temperature rises not only while the vehicle is traveling but also while parking and leaving the vehicle in summer. In many cases, the electric storage device is disposed under a floor of the vehicle, under a trunk room, or the like, and although the amount of heat per unit time given to the secondary batteries 12 a and 12 b is small, the battery temperature gradually rises by leaving the secondary batteries 12 a and 12 b for a long time.

When the secondary batteries 12 a and 12 b are left in a high-temperature state, the life of the secondary batteries 12 a and 12 b is greatly reduced, so that it is desired to maintain the battery temperature at a low temperature by cooling the secondary batteries 12 a and 12 b even while the vehicle is left.

The secondary batteries 12 a and 12 b according to the present embodiment are configured as an assembled battery in which the multiple battery cells 13 are stacked in a vehicle traveling direction, but if there is a variation in the temperature of each battery cell 13, the deterioration of the battery cells 13 is biased, and the performance of the electric storage device is deteriorated.

This is because the input and output characteristics of the electric storage device are determined in accordance with the characteristics of the most deteriorated battery cell 13. For that reason, in order for the electric storage device to exhibit a desired performance over a long period of time, it is important to equalize the temperatures of the multiple battery cells 13 so as to reduce temperature variations among the multiple battery cells 13.

As other cooling devices for cooling the secondary batteries 12 a and 12 b, blowing by a blower, air cooling using a refrigeration cycle, water cooling, or direct refrigerant cooling have been generally used, but the blower only blows the air in a vehicle compartment, so that the cooling capacity of the blower is low.

In addition, since the secondary batteries 12 a and 12 b are cooled by sensible heat of air in blowing by the blower, a temperature difference between the upstream and downstream of an air flow becomes large, and a temperature variation between the battery cells 13 cannot be sufficiently reduced.

In addition, although the cooling capacity is high in the refrigeration cycle system, since a heat exchange portion with the battery cells 13 is sensible cooling in either air cooling or water cooling, a temperature variation between the battery cells 13 cannot be sufficiently reduced. Further, it is not preferable to drive a compressor and a cooling fan of the refrigeration cycle during parking and leaving of the vehicle, because this causes an increase in power consumption, noise, and the like.

From the viewpoint of the above background, in the battery cooling unit 10 according to the present embodiment, a thermosiphon system is employed in which the secondary batteries 12 a and 12 b are cooled by natural convection of a refrigerant without using a compressor.

Specifically, as shown in FIG. 1, the battery cooling unit 10 includes a cooler 14, a condenser 16, an outward pipe 18, and a return pipe 20. The condenser 16, the outward pipe 18, the cooler 14, and the return pipe 20 are annularly connected to each other to configure a thermosiphon circuit 26 in which a refrigerant as a refrigerant of the battery cooling unit 10 circulates.

In other words, the thermosiphon circuit 26 configures a thermosiphon that performs a heat transfer by evaporation and condensation of the refrigerant. The thermosiphon circuit 26 is configured to provide a loop thermosiphon (in other words, a circulation circuit of the refrigerant) in which one flow channel through which a gas-phase refrigerant flows and the other flow channel through which a liquid-phase refrigerant flows are separated from each other.

In the respective drawings, an arrow DR1 indicates a direction of gravity, and in the arrow DR1, an up arrow indicates an upper side in the direction of gravity of the vehicle, and a down arrow indicates a lower side in the direction of gravity of the vehicle. An arrow DR2 indicates a vertical direction of the battery cooling unit 10 with the battery cooling unit 10 mounted on the vehicle. An arrow DR3 indicates a horizontal direction. When the traveling direction of the vehicle coincides with the horizontal direction, the direction of gravity coincides with the vertical direction. An arrow DR4 indicates the vehicle traveling direction. An arrow DR5 indicates a vehicle widthwise direction (that is, a left-right direction of the vehicle).

The thermosiphon circuit 26 according to the present embodiment is filled with a refrigerant. The thermosiphon circuit 26 is filled with the refrigerant. The refrigerant circulates through the thermosiphon circuit 26 by natural convection, and the battery cooling unit 10 adjusts the temperatures of the secondary batteries 12 a and 12 b by a phase change between the liquid phase and the gas phase of the refrigerant. More specifically, the secondary batteries 12 a and 12 b are cooled by the phase change of the refrigerant.

The refrigerant filled in the thermosiphon circuits 26 is, for example, a fluorocarbon refrigerant such as HFO-1234yf or HFC-134a. Alternatively, as the refrigerant, various working fluids other than the fluorocarbon refrigerant such as water and ammonia may be used.

As shown in FIG. 3, the cooler 14 is a heat exchanger disposed between the secondary batteries 12 a and 12 b to cool the secondary batteries 12 a and 12 b by exchanging a heat between the secondary batteries 12 a and 12 b and the refrigerant to transfer the heat from the secondary batteries 12 a and 12 b to the refrigerant. The cooler 14 is made of, for example, a metal having a high thermal conductivity.

In this example, the amount of the refrigerant filled in the thermosiphon circuit 26 is the amount of liquid-phase refrigerant with which the inside of the cooler 14 is filled in a state in which the heat exchange between the secondary batteries 12 a and 12 b and the refrigerant is stopped and the traveling direction of the vehicle coincides with the horizontal direction.

As shown in FIG. 2, an inlet 14 a and an outlet 14 b are provided in the cooler 14. The inlet 14 a and the outlet 14 b are provided on a front side of the cooler 14 in the vehicle traveling direction. The outlet 14 b is disposed above the inlet 14 a in a vertical direction.

An outward flow passage 18 a provided inside the outward pipe 18 communicates with the inside of the cooler 14. Therefore, when the refrigerant circulates in the thermosiphon circuit 26, the liquid-phase refrigerant in the outward flow passage 18 a flows into the cooler 14 through the inlet 14 a.

The outward flow passage 18 a is a flow channel of the refrigerant which allows the liquid-phase refrigerant to flow from the condenser 16 to the cooler 14. The outlet 14 b of the cooler 14 communicates a return flow passage 20 a provided in the return pipe 20 with the inside of the cooler 14.

Therefore, when the refrigerant circulates in the thermosiphon circuit 26, the gas-phase refrigerant in the cooler 14 exits to the return flow passage 20 a through the outlet 14 b. The return flow passage 20 a is a refrigerant flow channel for allowing the gas-phase refrigerant to flow from the outlet 14 b of the cooler 14 to the condenser 16.

The cooler 14 has a structure (not shown) in which the gas-phase refrigerant is exclusively discharged from the outlet 14 b of the inlet 14 a and the outlet 14 b.

The condenser 16 is a heat exchanger that exchanges a heat between the gas-phase refrigerant and a heat receiving fluid in the condenser 16 to radiate the heat from the refrigerant to the heat receiving fluid. In detail, the gas-phase refrigerant flows into the condenser 16 from the return pipe 20, and the condenser 16 condenses the refrigerant by radiating the heat from the refrigerant to the heat receiving fluid.

The heat receiving fluid that exchanges the heat with the refrigerant in the condenser 16 is, for example, air (that is, air of a vehicle exterior) or water.

The condenser 16 according to the present embodiment is installed so as to be positioned above the cooler 14 in the vertical direction even when the vehicle traveling direction (or the vehicle width direction) of the vehicle is inclined with respect to the horizontal direction.

The condenser 16 is disposed above the cooler 14 in the direction of gravity. In the present embodiment, the condenser 16 is accommodated in a front storage chamber or a trunk room. The front storage chamber is a chamber which is disposed on a front side of the vehicle relative to the vehicle compartment in the vehicle traveling direction and houses a traveling engine and a traveling electric motor. The trunk room is a storage room which is disposed on a rear side of the vehicle relative to the vehicle compartment in the vehicle traveling direction and stores a cargo and the like.

The return pipe 20 is connected to an upper portion of the condenser 16 in the direction of gravity. In short, the return pipe 20 is connected to the condenser 16 above the outward pipe 18 in the direction of gravity.

Next, the details of a cooling structure of the cooler 14 according to the present embodiment will be described.

The cooler 14 is a heat exchanger that includes evaporators 30 a, 30 b, 30 c, 30 d, . . . , 30 m stacked on each other in the vehicle traveling direction, for cooling the secondary batteries 12 a and 12 b. In the present embodiment, the evaporators 30 a to 30 m are provided for the respective battery cells 13 of the secondary batteries 12 a and 12 b (refer to FIGS. 4 and 9).

In FIG. 4, illustration except for the evaporators 30 a, 30 b, and 30 c among the evaporators 30 a, 30 b, 30 c, to, 30 m is omitted.

The secondary battery 12 a is disposed on one side of the evaporators 30 a to 30 m in the vehicle width direction. The secondary battery 12 a includes the multiple battery cells 13 stacked in the vehicle traveling direction. In other words, the multiple battery cells 13 are stacked in the same direction as the stacking direction of the evaporators 30 a to 30 m.

The secondary battery 12 b is disposed on the other side of the evaporators 30 a to 30 m in the vehicle width direction. The secondary battery 12 b includes the multiple battery cells 13 stacked in the vehicle traveling direction.

The secondary batteries 12 a and 12 b are the same secondary batteries, although the secondary batteries 12 a and 12 b are denoted by different symbols for convenience of description.

Each of heat conduction materials 40 a and 40 b is formed in a thin plate-shape and made of a material having an electrical insulation property and a high thermal conductivity. The heat conduction material 40 a is disposed between the evaporators 30 a to 30 m and the secondary battery 12 a. The heat conduction material 40 b is disposed between the evaporators 30 a to 30 m and the secondary battery 12 b.

The heat conduction materials 40 a and 40 b according to the present embodiment may have an effect of absorbing dimensional errors of the evaporators 30 a to 30 m and the secondary batteries 12 a and 12 b.

Each of the evaporators 30 a to 30 m according to the present embodiment is formed in a block shape in which a dimension in the vertical direction is larger than a dimension in the vehicle traveling direction, and the dimension in the vertical direction is larger than a dimension in the vehicle width direction.

The evaporators 30 a to 30 m are aligned in the order of the evaporator 30 a, the evaporator 30 b, the evaporator 30 c, to, the evaporator 30 m from the front side in the vehicle traveling direction to the rear side in the vehicle traveling direction to configure a block stacked structure. In other words, the alignment direction of the evaporators 30 a to 30 m according to the present embodiment is the same as the vehicle traveling direction.

Next, the structure of the evaporator 30 a will be described using the evaporator 30 a as a representative of the evaporators 30 a to 30 m of the present embodiment.

The evaporator 30 a includes a case 40 formed in a rectangular parallelepiped shape and a lid portion 50. The case 40 provides an opening portion that opens to the front side in the vehicle traveling direction.

The case 40 includes an upper surface 41, a lower surface 42, side surfaces 43 and 44, and a back surface 45. The upper surface 41 provides an opening in cooperation with the lower surface 42 and the side surfaces 43 and 44. The back surface 45 is disposed on the rear side of the upper surface 41, the lower surface 42, and the side surfaces 43 and 44 in the vehicle traveling direction.

The lid portion 50 in FIG. 4 closes the opening of the case 40. The lid portion 50 is provided with the inlet 14 a and the outlet 14 b penetrating in the vehicle traveling direction. In other words, the inlet 14 a and the outlet 14 b are disposed on the front side of the evaporators 30 a to 30 m in the vehicle traveling direction.

An outlet of the condenser 16 is connected to the inlet 14 a through the outward pipe 18. The outlet 14 b communicates with an upper region of a gas-liquid separation chamber 62 of the evaporator 30 a in the direction of gravity. The outlet 14 b is connected to the inlet of the condenser 16 through the return pipe 20.

In the case 40, partition walls 60 a, 60 b, and 60 c are provided. Each of the partition walls 60 a and 60 b is formed in a plate-shape extending in the direction of gravity. The partition walls 60 a and 60 b are aligned in the vehicle width direction.

The partition wall 60 a provides an evaporation flow channel 61 a that exchanges a heat between the refrigerant and the secondary battery 12 a, in cooperation with the side surface 43. The evaporation flow channel 61 a is formed so as to extend upward in the vertical direction along the partition wall 60 a and the side surface 43.

The partition wall 60 b provides an evaporation flow channel 61 b that exchanges a heat between the refrigerant and the secondary battery 12 b, in cooperation with the side surface 44. The evaporation flow channel 61 b is provided so as to extend upward in the vertical direction along the partition wall 60 b and the side surface 44.

The evaporation flow channels 61 a and 61 b are configured by the partition walls 60 a and 60 b as a second flow channel forming member, the side surfaces 43 and 44, and the like.

In the evaporation flow channels 61 a and 61 b according to the present embodiment, a wick (capillary structure) may be provided or a heat exchange fin may be incorporated. As a result, the heat exchange between the refrigerant and the secondary batteries 12 a and 12 b can be promoted, so that evaporation of the refrigerant can be promoted.

The gas-liquid separation chamber 62 and a liquid-phase refrigerant supply chamber 63 are provided between the partition walls 60 a and 60 b. The partition wall 60 c is formed so as to separate the gas-liquid separation chamber 62 and the liquid-phase refrigerant supply chamber 63 from each other.

The gas-liquid separation chamber 62 is formed above the partition wall 60 c in the direction of gravity. As will be described later, the gas-liquid separation chamber 62 separates the refrigerant supplied from the evaporation flow channels 61 a and 61 b into a gas-phase refrigerant and a liquid-phase refrigerant. The liquid-phase refrigerant supply chamber 63 is provided on the lower side of the partition wall 60 c in the direction of gravity.

The upper side of the liquid-phase refrigerant supply chamber 63 of the evaporator 30 a according to the present embodiment in the vertical direction configures one refrigerant supply flow channel 70 together with the upper side of the liquid-phase refrigerant supply chamber 63 of the evaporators 30 b to 30 m in the vertical direction, as will be described later.

The lower side of the liquid-phase refrigerant supply chamber 63 of the evaporator 30 a in the vertical direction is formed so as to be recessed downward from the refrigerant supply flow channel 70, and configures a liquid storage 63 a for storing the liquid-phase refrigerant from the refrigerant supply flow channel 70.

An inlet 64 a of the evaporation flow channel 61 a is provided between the partition wall 60 a and the lower surface 42. The inlet 64 a communicates with the liquid storage 63 a, and the liquid-phase refrigerant from the liquid storage 63 a flows into the inlet 64 a. The inlet 64 a is located on the lower side of the refrigerant supply flow channel 70 in the vertical direction. In other words, the inlet 64 a is located below a communication opening portion 68 in the vertical direction. The inlet 64 a communicates with the liquid storage 63 a. As a result, the inlet 64 a communicates with the refrigerant supply flow channel 70 through the liquid storage 63 a.

An inlet 64 b of the evaporation flow channel 61 b is provided between the partition wall 60 b and the lower surface 42. The inlet 64 b communicates with the liquid storage 63 a to allow the liquid-phase refrigerant from the liquid storage 63 a to flow in the inlet 64 b. The inlet 64 b is located on the lower side of the refrigerant supply flow channel 70 in the vertical direction. In other words, the inlet 64 b is located on the lower side of the communication opening portion 68 in the vertical direction. The inlet 64 b communicates with the liquid storage 63 a. As a result, the inlet 64 b communicates with the refrigerant supply flow channel 70 through the liquid storage 63 a.

A communication passage 65 a is provided between the partition wall 60 a and the upper surface 41 to communicate between the evaporation flow channel 61 a and the gas-liquid separation chamber 62 and supply the refrigerant from the evaporation flow channel 61 a to the gas-liquid separation chamber 62.

A communication passage 65 b is provided between the partition wall 60 b and the upper surface 41 to communicate between the evaporation flow channel 61 b and the gas-liquid separation chamber 62 and supply the refrigerant from the evaporation flow channel 61 b to the gas-liquid separation chamber 62.

The partition wall 60 c is provided with a refrigerant return flow channel 66 for communicating between the gas-liquid separation chamber 62 and the liquid-phase refrigerant supply chamber 63. The refrigerant return flow channel 66 returns the liquid-phase refrigerant in the gas-liquid separation chamber 62 to the liquid-phase refrigerant supply chamber 63.

A communication hole 67 communicating with the gas-liquid separation chamber 62 of the evaporator 30 b is provided in the back surface 45 on the upper side of the partition wall 60 c in the direction of gravity. The evaporator 30 b is disposed on the rear side of the evaporator 30 a in the vehicle traveling direction.

In other words, in the two adjacent evaporators 30 a and 30 b, the gas-liquid separation chambers 62 communicate with each other through the communication hole 67.

A communication opening portion 68 penetrating in the vehicle traveling direction is provided in the back surface 45 on the lower side of the partition wall 60 c in the direction of gravity. In other words, the communication opening portion 68 of the evaporator 30 a communicates between the liquid-phase refrigerant supply chamber 63 of the evaporator 30 a and the liquid-phase refrigerant supply chamber 63 of the evaporator 30 b.

In the back surface 45, the communication opening portion 68 is formed in a pentagonal shape. For that reason, a lower edge portion 68 a forming a lower side of the communication opening portion 68 in the back surface 45 is formed in a V-shape which is positioned on the upper side in the vertical direction from the center portion in the vehicle width direction toward a right side in the vehicle width direction, and is positioned on the upper side in the vertical direction from the center portion in the vehicle width direction toward the left side in the vehicle width direction.

A back wall 69 functioning as a weir for damming the liquid-phase refrigerant is formed on the back surface 45 on a lower side of the communication opening portion 68 in the direction of gravity. For that reason, the back wall 69 of the evaporator 30 a is a wall that partitions the liquid storage 63 a of each of the two adjacent evaporators 30 a and 30 b. The liquid storage 63 a of the evaporator 30 a is partitioned by the lower surface 42, the partition walls 60 a and 60 b, the back wall 69, and the lid portion 50.

The lid portion 50 and the partition walls 60 a, 60 b, and 60 c according to the present embodiment are made of a metal material such as aluminum.

The evaporators 30 b to 30 m according to the present embodiment include a case 40 and partition walls 60 a, 60 b, and 60 c.

The case 40 in the evaporator 30 a and the case 40 in the evaporators 30 b to 30 m are the same.

The partition walls 60 a, 60 b, and 60 c in the evaporator 30 a and the partition walls 60 a, 60 b, and 60 c in the evaporators 30 b to 30 m are the same.

However, the back surface 45 of the case 40 of the evaporator 30 m located on the rearmost side among the evaporators 30 a to 30 m in the vehicle traveling direction is closed by eliminating the communication hole 67 and the communication opening portion 68 (refer to A and B of FIG. 8).

The opening of the case 40 of the rear evaporator of two adjacent evaporators among the evaporators 30 a to 30 m in the vehicle traveling direction is closed by the back surface 45 of the case 40 of the evaporator on one side in the vehicle traveling direction.

For example, the opening of the case 40 of the rear evaporator 30 b of the two adjacent evaporators 30 a and 30 b in the vehicle traveling direction is closed by the back surface 45 of the case 40 of the evaporator 30 a on one side in the vehicle traveling direction.

For that reason, similarly to the evaporator 30 a, each of the evaporators 30 b to 30 m includes a gas-liquid separation chamber 62, a liquid-phase refrigerant supply chamber 63, and a liquid storage 63 a. The gas-liquid separation chamber 62 of each of the evaporators 30 b to 30 m separates the refrigerant supplied from the evaporation flow channels 61 a and 61 b into a gas-phase refrigerant and a liquid-phase refrigerant.

In this example, the gas-liquid separation chambers 62 of two adjacent evaporators among the evaporators 30 a to 30 m communicate with each other through the communication hole 67. The gas-liquid separation chamber 62 of each of the evaporators 30 a to 30 m provides one gas-phase refrigerant flow channel 71 (refer to FIG. 9) for guiding the gas-phase refrigerant in the gas-liquid separation chamber 62 to the outlet 14 b together with the communication hole 67 of each evaporator.

The gas-phase refrigerant flow channel 71 is provided by the partition walls 60 a and 60 b as the third flow channel forming member and the back surface 45.

A lower side of gas-liquid separation chamber 62 of each of the evaporators 30 a to 30 m according to the present embodiment with respect to the gas-phase refrigerant flow channel 71 in the direction of gravity functions to store the liquid-phase refrigerant subjected to the gas-liquid separation.

The liquid storage 63 a of each of the evaporators 30 b to 30 m is partitioned for each evaporator by the lower surface 42, the partition walls 60 a and 60 b, and the two back walls 69. The two back walls 69 are the respective back walls 69 of two adjacent evaporators of the evaporators 30 b to 30 m.

For example, the liquid storage 63 a of the evaporator 30 b is formed between the back wall 69 of the evaporator 30 a and the back wall 69 of the evaporator 30 b. The liquid storage 63 a of the evaporator 30 c is formed between the back wall 69 of the evaporator 30 b and the back wall 69 of the evaporator 30 c.

The liquid-phase refrigerant supply chambers 63 of two adjacent evaporators of the evaporators 30 a to 30 m communicate with each other through the communication opening portion 68.

Upper sides of the respective liquid-phase refrigerant supply chambers 63 of the evaporators 30 a to 30 m in the vertical direction according to the present embodiment communicate with each other through the respective communication opening portions 68 of the evaporators 30 a to 30 k, and configure one refrigerant supply flow channel 70.

In other words, the respective liquid storages 63 a of the evaporators 30 b to 30 m are formed below the communication opening portions 68 in the liquid-phase refrigerant supply chamber 63.

The refrigerant supply flow channel 70 according to the present embodiment is configured by the partition walls 60 a, 60 b, 60 c, and the like as a first flow channel configuring portion.

In the evaporators 30 a to 30 m configured as described above, the evaporation flow channels 61 a and 61 b, the gas-liquid separation chamber 62, and the liquid-phase refrigerant supply chamber 63 are provided for each evaporator. In addition, in the evaporators 30 a to 30 m, one refrigerant supply flow channel 70 is configured to supply the liquid-phase refrigerant flowing in from the condenser 16 through the inlet 14 a to the liquid storage 63 a of each evaporator. The evaporation flow channels 61 a (or 61 b) of the evaporators 30 a to 30 m are aligned in the refrigerant flow direction of the refrigerant supply flow channel 70.

A flow channel cross-sectional area of the evaporation flow channel 61 a according to the present embodiment is smaller than a flow channel cross-sectional area of the refrigerant supply flow channel 70. A flow channel cross-sectional area of the evaporation flow channel 61 b is smaller than the flow channel cross-sectional area of the refrigerant supply flow channel 70.

In this example, the flow channel cross-sectional area of the evaporation flow channel 61 a is an area of a cross section of the evaporation flow channel 61 a taken in a direction orthogonal to the refrigerant flow direction. The flow channel cross-sectional area of the evaporation flow channel 61 b is an area of a cross section of the evaporation flow channel 61 b taken in a direction orthogonal to the refrigerant flow direction.

The flow channel cross-sectional area of the refrigerant supply flow channel 70 is an area of a cross section of the refrigerant supply flow channel 70 taken in a direction orthogonal to the refrigerant flow direction. The flow channel cross-sectional area of the refrigerant supply flow channel 70 according to the present embodiment matches an opening area of the communication opening portion 68.

A lower side of the evaporation flow channel 61 a of the evaporator 30 a in the vertical direction according to the present embodiment faces a lower side of the secondary battery 12 a in the vertical direction across the heat conduction material 40 a. A lower side of the evaporation flow channel 61 b of the evaporator 30 a in the vertical direction faces a lower side of the secondary battery 12 b in the vertical direction across the heat conduction material 40 b.

Similarly, a lower side of the evaporation flow channel 61 a of each of the evaporators 30 b to 30 m in the vertical direction faces a lower side of the secondary battery 12 a across the heat conduction material 40 a in the vertical direction. A lower side of the evaporation flow channel 61 b of each of the evaporators 30 b to 30 m in the vertical direction faces a lower side of the secondary battery 12 b across the heat conduction material 40 b in the vertical direction.

Next, the operation of the battery cooling unit 10 according the present embodiment will be described.

First, when the temperature of the secondary batteries 12 a and 12 b is the same as the temperature of the liquid-phase refrigerant in the evaporators 30 a to 30 m, a heat exchange between the secondary batteries 12 a and 12 b and the liquid-phase refrigerant in the evaporators 30 a to 30 m is stopped.

In this example, when the vehicle width direction coincides with the horizontal direction and the vehicle traveling direction coincides with the horizontal direction, the battery cooling unit 10 assumes a specified posture (hereinafter referred to as a reference posture).

At that time, the inside of the thermosiphon circuit 26 is filled with the refrigerant so that the liquid-phase refrigerant is filled in the evaporation flow channels 61 a and 61 b of the evaporators 30 a to 30 m.

At that time, a liquid surface ha of the liquid-phase refrigerant is located in the evaporation flow channels 61 a and 61 b and the liquid storage 63 a of the evaporators 30 a to 30 m.

Thereafter, the secondary batteries 12 a and 12 b generate heat, and the temperature of the secondary batteries 12 a and 12 b increases. Then, the heat is transferred from the secondary battery 12 a to the side surfaces 43 of the cases 40 of the evaporators 30 a to 30 m through the heat conduction material 40 a. The heat is transferred from the secondary battery 12 b through the heat conduction material 40 b to the side surfaces 44 of the cases 40 of the evaporators 30 a to 30 m as indicated by an arrow Nb.

In this manner, the liquid-phase refrigerant in the evaporation flow channels 61 a and 61 b in the evaporators 30 a to 30 m boils by the heat transferred from the secondary batteries 12 a and 12 b to the evaporators 30 a to 30 m through the heat conduction materials 40 a and 40 b.

As a result, the refrigerant evaporates from the inside of the liquid-phase refrigerant in the evaporation flow channels 61 a and 61 b in the evaporators 30 a to 30 m. For that reason, as the liquid-phase refrigerant boils, air bubbles containing the gas-phase refrigerant are generated from the inside of the liquid-phase refrigerant.

At that time, in the evaporation flow channels 61 a and 61 b, a volume of the liquid-phase refrigerant containing the air bubbles becomes larger than a volume of the liquid-phase refrigerant containing no air bubbles at the time of stopping the heat exchange. For that reason, a liquid surface of the liquid-phase refrigerant in the evaporation flow channels 61 a and 61 b (refer to “ha” in FIG. 5) rises above a liquid surface of the liquid-phase refrigerant when the vehicle is stopped.

In other words, in the evaporation flow channels 61 a and 61 b, the liquid surface of the liquid-phase refrigerant in the evaporation flow channels 61 a and 61 b rises due to the air bubble pump effect in which the liquid-phase refrigerant containing the air bubbles rises as a bubble mixed flow.

At that time, the liquid-phase refrigerant is supplied to the upper side of the evaporation flow channels 61 a and 61 b in the vertical direction, and the liquid-phase refrigerant is evaporated by taking heat of the secondary batteries 12 a and 12 b and becomes a gas-phase refrigerant.

At that time, when the liquid surface of the liquid-phase refrigerant in the evaporation flow channel 61 a reaches the communication passage 65 a, the bubble mixed flow in the communication passage 65 a flows into the gas-liquid separation chamber 62 by gravity.

When the liquid surface of the liquid-phase refrigerant in the evaporation flow channel 61 b reaches the communication path 65 b, the bubble mixed flow in the communication passage 65 b flows into the gas-liquid separation chamber 62 by gravity.

In other words, the bubble mixed flows in the communication passages 65 a and 65 b join in the gas-liquid separation chamber 62. At that time, the bubble mixed flow is separated into the gas-phase refrigerant and the liquid-phase refrigerant in the gas-phase refrigerant flow channel 71. The gas-phase refrigerant flows to the outlet 14 b through the gas-phase refrigerant flow channel 71 as indicated by an arrow Ka in FIG. 9. The liquid-phase refrigerant is stored in the lower side of the gas-liquid separation chamber 62 in the vertical direction. Then, the liquid-phase refrigerant in the gas-liquid separation chamber 62 returns to the liquid-phase refrigerant supply chamber 63 through the refrigerant return flow channel 66 a.

As a result, a total amount of the bubble mixed flow in the evaporation flow channels 61 a and 61 b can be reduced, so that the liquid surface of the liquid-phase refrigerant is prevented from moving upward in the direction of gravity relative to the outlet 14 b.

In other words, the liquid surface of the liquid-phase refrigerant is inhibited from moving above the evaporators 30 a to 30 m in the direction of gravity. This makes it possible to reduce the “region where the liquid-phase refrigerant containing air bubbles exists” which is a sound source for generating abnormal noise. Therefore, abnormal noise caused by boiling of the liquid-phase refrigerant can be reduced.

In addition, since the liquid-phase refrigerant is stored in the gas-liquid separation chamber 62 when the liquid-phase refrigerant in the evaporation flow channels 61 a and 61 b boils, the amount of the liquid-phase refrigerant containing air bubbles in the evaporation flow channels 61 a and 61 b is reduced. For that reason, the fluctuation of the liquid surface of the refrigerant becomes small. Therefore, vibration caused by boiling of the liquid-phase refrigerant is reduced.

On the other hand, the gas-phase refrigerant moves from the outlet 14 b to the condenser 16 through the return flow passage 20 a of the return pipe 20.

At that time, when the temperature of the secondary batteries 12 a and 12 b becomes higher than the temperature of the condenser 16, or when the temperature of the condenser 16 becomes lower than the temperature of the secondary batteries 12 a and 12 b, condensation of the liquid-phase refrigerant starts in the condenser 16. At that time, in the condenser 16, the gas-phase refrigerant radiates a heat to the heat receiving fluid and the gas-phase refrigerant condenses. The condensed liquid-phase refrigerant flows through the outward flow passage 18 a of the outward pipe 18 to the inlet 14 a of the cooler 14 by gravity.

Then, the liquid-phase refrigerant flows through the refrigerant supply flow channel 70 to the respective liquid storages 63 a of the evaporators 30 a to 30 m.

Specifically, the liquid-phase refrigerant flows in the order of the liquid storage 63 a of the evaporator 30 a, the liquid storage 63 a of the evaporator 30 b, the liquid storage 63 a of the evaporator 30 c, the liquid storage 63 a of the evaporator 30 d, . . . the liquid storage 63 a of the evaporator 30 m.

In other words, while the liquid storage unit 63 a is filled with the liquid-phase refrigerant in each evaporator, the liquid-phase refrigerant sequentially flows from the liquid storage 63 a of the evaporator on the front side in the vehicle traveling direction to the liquid storage unit 63 a of the evaporator on the rear side in the vehicle traveling direction.

In the evaporators 30 a to 30 m, the liquid-phase refrigerant flows from the liquid storage 63 a to the evaporation flow channels 61 a and 61 b.

As described above, in the battery cooling unit 10 according to the present embodiment, the above operations are performed by natural circulation of the refrigerant enclosed in the thermosiphon circuit 26 without requiring a drive device such as a compressor. The natural circulation is the circulation of the refrigerant in the thermosiphon circuit 26 due to the natural convection caused by a temperature difference between the condenser 16 and the evaporators 30 a to 30 m.

For example, when the vehicle is climbing an upward slope, the vehicle traveling direction is inclined with respect to the horizontal direction, and the front side of the battery cooling unit 10 in the vehicle traveling direction is located above the rear side of the vehicle traveling direction in the vertical direction.

Alternatively, when the vehicle is descending on a downhill slope or the like, the rear side of the battery cooling unit 10 in the vehicle traveling direction is higher than the front side in the vehicle traveling direction in the vertical direction.

Depending on a road on which the vehicle travels, the vehicle width direction becomes oblique with respect to the horizontal direction, and the right side of the battery cooling unit 10 in the vehicle width direction becomes higher than the left side in the vehicle width direction in the vertical direction.

Alternatively, depending on the road on which the vehicle travels, the left side of the battery cooling unit 10 in the vehicle width direction may be located above the right side in the vehicle width direction in the vertical direction.

Further, when the road surface on which the vehicle stops is inclined, the vehicle traveling direction (or the vehicle width direction) may become oblique with respect to the horizontal direction.

When the vehicle traveling direction (or the vehicle width direction) is inclined with respect to the horizontal direction in this manner, the battery cooling unit 10 is inclined with respect to the reference posture described above.

In this example, as described above, the liquid storage 63 a of each of the evaporators 30 a to 30 m is surrounded by the partition walls 60 a and 60 b and the two back walls 69 for each evaporator.

For that reason, even when the battery cooling unit 10 is inclined from the reference posture described above, the liquid-phase refrigerant in the liquid storage 63 a for each evaporator is held in the liquid storage 63 a. In other words, when the battery cooling unit 10 is inclined with respect to the reference posture described above, the liquid-phase refrigerant is prevented from flowing out of the liquid storage 63 a through the communication opening portion 68.

Further, in the present embodiment, the inlet 64 a of the evaporation flow channel 61 a is located on the lower side in the vertical direction than the center in the vertical direction of the refrigerant supply flow channel 70.

However, when the position of the refrigerant supply flow channel 70 on the uppermost side in the vertical direction is defined as the uppermost position and the position of the refrigerant supply flow channel 70 on the lowermost side in the vertical direction is defined as the lowermost position, the center of the refrigerant supply flow channel 70 in the vertical direction is a middle between the uppermost portion and the lowermost portion.

More specifically, the inlet 64 a of the evaporation flow channel 61 a communicates with the lower side of the liquid storage 63 a in the vertical direction. The inlet 64 b of the evaporation flow channel 61 b communicates with the lower side of the liquid storage 63 a in the vertical direction.

For that reason, even if the battery cooling unit 10 is inclined with respect to the reference posture described above and the supply amount of the liquid-phase refrigerant supplied from the refrigerant supply flow channel 70 to the liquid storage 63 a of each evaporator is small, the liquid surface of the liquid-phase refrigerant is easily positioned above the inlet 64 a (or 64 b) of the evaporation flow channel 61 a (or 61 b) in the vertical direction.

In other words, even if the battery cooling unit 10 is inclined with respect to the reference posture described above and the supply amount of the liquid-phase refrigerant supplied to the liquid storage 63 a of each evaporator is small, the inlet 64 a of the evaporation flow channel 61 a (or 61 b) is located at the same height as the liquid surface of the liquid-phase refrigerant in the liquid storage 53 a of each evaporator or below the liquid surface of the liquid-phase refrigerant in the liquid storage 53 a of each evaporator.

Therefore, the supply amount of the liquid-phase refrigerant supplied from the liquid storage 63 a to the evaporation flow channels 61 a and 61 b is stabilized for each evaporator.

According to the present embodiment described above, the cooler 14 has the communication opening portion 68 for each section of the refrigerant supply flow channel 70 (that is, for each evaporator), but the back wall 69 (that is, a weir) and the liquid storage 63 a are formed at a position lower than a lower end of the communication opening portion 68.

The liquid-phase refrigerant can be retained in the liquid storage 63 a even when the vehicle is inclined, and when the liquid-phase refrigerant supplied from the upstream at the time of the inclination fills the upstream liquid storage 63 a, the liquid-phase refrigerant flows out to the downstream liquid storage 63 a and fills the downstream side liquid storage 63 a one after another.

The refrigerant inlets 64 a and 64 b of the evaporation flow channels 61 a and 61 b communicate with each other at the same height as the liquid surface at the time of inclination or at a position lower than the liquid surface in the liquid storage 63 a of each evaporator. For that reason, the liquid-phase refrigerant is supplied from the refrigerant inlets 64 a and 64 b to the lower side of the evaporation flow channels 61 a and 61 b.

The liquid-phase refrigerant receives heat from the secondary batteries 12 a and 12 b (that is, an object to be cooled) under the evaporation flow channels 61 a and 61 b of each of the liquid storages 63 a (that is, each section), takes the heat, and starts evaporation. Then, the liquid-phase refrigerant below the evaporation flow channels 61 a and 61 b becomes a bubble flow due to the buoyancy of the generated bubbles and the viscosity of the liquid, and pushes up the liquid surface from the lower part in the evaporation flow channels 61 a and 61 b to the upper part in the evaporation flow channels 61 a and 61 b by the bubble pump effect.

As a result, the liquid-phase refrigerant under the evaporation flow channels 61 a and 61 b is further supplied to the upper portions of the evaporation flow channels 61 a and 61 b, thereby increasing an area for removing the heat from the secondary batteries 12 a and 12 b and increasing the cooling effect.

The gas-phase refrigerant separated from the bubble flow which has risen by evaporation of the liquid-phase refrigerant in the evaporation flow channels 61 a and 61 b returns to the condenser 16 through the return pipe 20, is condensed, and is supplied to the lower cooler 14 again as the liquid-phase refrigerant by gravity.

The liquid-phase refrigerant is continuously supplied to the cooler 14 while the temperature of the condenser 16 is lower than that of the liquid-phase refrigerant as described above, and the liquid-phase refrigerant can be stably supplied to the evaporators 30 a to 30 m from the upstream side to the downstream side at the time of inclination to each evaporator (that is, each section).

Even if the vehicle is inclined, if the temperature of the cooler 14 decreases and the temperature difference between the cooler 14 and the condenser 16 decreases, the refrigerant circulation amount decreases or the refrigerant circulation stops, and a partial dry portion occurs again. The heat generation of the battery cells 13 is substantially uniform, and therefore at the time when the high-temperature portion occurs again, the refrigerant circulation is started by evaporation from a portion immersed in the liquid, and the refrigerant is supplied to the evaporators 30 a to 30 m.

As described above, the battery cooling unit 10 includes the condenser 16 that condenses the gas-phase refrigerant and discharges the liquid-phase refrigerant, and the cooler 14 that configures a thermosiphon which circulates the refrigerant together with the condenser 16. The cooler 14 forms one refrigerant supply flow channel 70 through which the liquid-phase refrigerant from the condenser 16 flows, and provides the evaporation flow channels 61 a and 61 b having the refrigerant inlets 64 a and 64 b communicating with the refrigerant supply flow channel 70 for each evaporator.

The evaporation flow channels 61 a and 61 b evaporate the liquid-phase refrigerant by a heat exchange between the liquid-phase refrigerant flowing in from the refrigerant supply flow channel 70 through the refrigerant inlets 64 a and 64 b and the secondary batteries 12 a and 12 b, and allow the gas-phase refrigerant to flow toward the condenser 16.

The liquid storage 63 a for each evaporation communicates with the inlets 64 a and 64 b of the evaporation flow channels 61 a and 61 b of the evaporator corresponding to the evaporation flow channels 61 a and 61 b for each evaporator. The refrigerant inlets 64 a and 64 b are located on the lower side of the center portion of the refrigerant supply flow channel 70 in the vertical direction.

Therefore, even if the cooler 14 is inclined from a specified reference posture and the supply amount of the liquid-phase refrigerant from the condenser 16 to the cooler 14 is small, it is advantageous to provide the liquid surface of the liquid-phase refrigerant above the refrigerant supply flow channel 70 as compared with the case where the refrigerant inlets 64 a and 64 b are positioned above the center portion of the refrigerant supply flow channel 70 in the vertical direction.

As a result, the liquid-phase refrigerant can be stably supplied from the refrigerant supply flow channel 70 to the evaporation flow channels 61 a and 61 b. For that reason, cooling of the secondary batteries 12 a and 12 b can be stabilized.

When the thermosiphon cooler 14A (refer to FIG. 13A) is used to cool a large secondary battery, a dry portion of the cooler 14A may occur above the liquid surface of the liquid-phase refrigerant. When a temperature difference is generated between the secondary battery and the condenser due to heat generation of the secondary battery due to traveling of the vehicle, the condenser starts supplying the liquid-phase refrigerant, and the liquid-phase refrigerant starts descending.

Even if the liquid-phase refrigerant drips into the cooler 14A, if the cooler 14A is not provided with a liquid storage for each evaporator, when the cooler 14A (refer to FIG. 13B) is inclined with respect to the reference posture when the vehicle is climbing a slope, the liquid-phase refrigerant is biased downward in the direction of gravity. For that reason, the liquid-phase refrigerant cannot be successfully supplied to the evaporation flow channel extending upward, and the dry portion may become insufficiently cooled.

On the other hand, a temperature limitation of the secondary battery is controlled so that the temperature of the battery cell with the maximum temperature does not exceed an upper limit threshold, and therefore, if the temperature of the secondary battery that has become insufficient for cooling reaches an upper limit target value, the output of a battery pack (assembled battery) is limited or stopped so that a cell temperature of the highest temperature does not exceed the upper limit temperature even if the temperature of the other battery cells is low.

On the other hand, in the cooler 14 according to the present embodiment, the liquid storage 63 a is provided for each evaporator. For that reason, even if the cooler 14A is inclined from the reference posture, the refrigerant can be inhibited from collecting in the lowest portion of the cooler 14. Accordingly, the supply of the liquid-phase refrigerant from the liquid-phase refrigerant supply chamber 63 to the evaporation flow channels 61 a and 61 b can be stabilized for each evaporator. For that reason, a heat exchange between the liquid-phase refrigerant in the evaporation flow channels 61 a and 61 b and the secondary batteries 12A and 12B can be stabilized for each evaporator. This makes it possible to avoid the output limitation and stop of the battery pack in advance.

As described above, the output of an electric power from the battery pack to the electric motor can be prevented from being restricted due to the partial occurrence of a high-temperature portion in the secondary batteries 12A and 12B such that the output of the electric motor is lowered and the traveling is impossible.

In addition, the present embodiment eliminates a need to fill the cooler 14 with a large amount of liquid-phase refrigerant. This makes it possible to prevent a decrease in the gas-liquid separation of the refrigerant, a decrease in the refrigerant circulation, a decrease in the cooling performance of the secondary battery, an increase in the weight, an increase in the cost, and the like from occurring.

The flow channel cross-sectional areas of the evaporation flow channels 61 a and 61 b according to the present embodiment are smaller than the flow channel cross-sectional area of the refrigerant supply flow channel 70.

If the flow channel cross-sectional area of the evaporation flow channels 61 a and 61 b is excessively large, the air bubbles are easily separated from the liquid-phase refrigerant in the evaporation flow channels 61 a and 61 b, and the liquid surface of the liquid-phase refrigerant is difficult to rise in the evaporation flow channels 61 a and 61 b. For that reason, the supply amount of the liquid-phase refrigerant from the liquid storage 63 a to the evaporation flow channels 61 a and 61 b is also reduced.

On the contrary, as described above, the flow channel cross-sectional areas of the evaporation flow channels 61 a and 61 b according to the present embodiment are smaller than the flow channel cross-sectional area of the refrigerant supply flow channel 70. For that reason, the air bubbles are less likely to be separated from the liquid-phase refrigerant in the evaporation flow channels 61 a and 61 b. For that reason, the liquid surface of the liquid-phase refrigerant rises in the evaporation flow channels 61 a and 61 b, and the supply amount of the liquid-phase refrigerant from the liquid storage 63 a to the evaporation flow channels 61 a and 61 b also increases.

The lower edge portion 68 a forming the lower side of the communication opening portion 68 in the back surface 45 according to the present embodiment is formed in a V-shape. For that reason, even if the vehicle width direction is inclined with respect to the horizontal direction, the liquid-phase refrigerant can be prevented from moving between the liquid storages 63 a of two adjacent evaporators through the communication opening portion 68.

Second Embodiment

In a second embodiment, an example in which two coolers 14 of the first embodiment are connected in series to configure a battery cooling unit 10 will be described with reference to FIGS. 15 to 18.

The present embodiment differs from the first embodiment in a battery cooling structure in which secondary batteries 12 a and 12 b are cooled with the use of the coolers 14. For that reason, the battery cooling structure of the battery cooling unit 10 will be described below, and a description of the other components will be omitted.

The battery cooling unit 10 according to the present embodiment includes the two coolers 14 and two pairs of secondary batteries 12 a and 12 b as the battery cooling structure.

The two coolers 14 are respectively configured in the same manner as the cooler 14 of the first embodiment. The two coolers 14 are aligned in a vehicle traveling direction. Hereinafter, for convenience of description, a front cooler of the two coolers 14 in the vehicle traveling direction is defined as a cooler 14M, and a rear cooler of the two coolers 14 in the vehicle traveling direction is defined as a cooler 14U.

The coolers 14M and 14U are disposed such that a stacking direction of evaporators 30 a to 30 m coincides with a vehicle width direction. In other words, in each of the coolers 14M and 14U, a refrigerant supply flow channel 70 extends in the vehicle width direction. The vehicle width direction is a direction intersecting with the vehicle traveling direction, that is, a crossing direction.

An inlet 14 a and an outlet 14 b are provided on one side of the cooler 14M in the vehicle width direction. A refrigerant outlet 14 c is provided on the other side of the cooler 14M in the vehicle width direction. The refrigerant outlet 14 c communicates with the refrigerant supply flow channel 70 of the cooler 14M.

The outlet 14 b is provided on one side of the cooler 14U in the vehicle width direction. The inlet 14 a is provided on the other side of the cooler 14U in the vehicle width direction.

The outlet 14 c of the cooler 14M and the inlet 14 a of the cooler 14U are connected to each other by a refrigerant pipe 80. The refrigerant pipe 80 configures a refrigerant flow channel for guiding the liquid-phase refrigerant from the outlet 14 c of the cooler 14M to the inlet 14 a of the cooler 14U.

The cooler 14M is disposed between a pair of secondary batteries 12 a and 12 b. The pair of secondary batteries 12 a and 12 b are aligned in the vehicle traveling direction across the cooler 14M.

The cooler 14U is disposed between the pair of secondary batteries 12 a and 12 b. The pair of secondary batteries 12 a and 12 b are aligned in the vehicle traveling direction across the cooler 14U.

In each of the two pairs of secondary batteries 12 a and 12 b according to the present embodiment, a stacking direction of the battery cells 13 coincides with the vehicle width direction.

In the present embodiment configured as described above, a liquid-phase refrigerant flows from a condenser 16 through the inlet 14 a of the cooler 14M into the refrigerant supply flow channel 70. For that reason, the liquid-phase refrigerant is sequentially supplied to respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14M.

Thereafter, the liquid-phase refrigerant discharged from the refrigerant supply flow channel 70 through the outlet 14 c flows to the refrigerant supply flow channel 70 from the inlet 14 a of the cooler 14U through the refrigerant pipe 80. For that reason, the liquid-phase refrigerant is sequentially supplied to the respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14U.

As described above, the liquid-phase refrigerant is sequentially supplied to the liquid storages 63 a of the evaporators of each of the coolers 14M and 14U aligned in the vehicle traveling direction and connected in series. For that reason, the evaporators 30 a to 30 n of the coolers 14M and 14U operate in the same manner as in the first embodiment. For that reason, the two pairs of secondary batteries 12 a and 12 b can be cooled by the coolers 14M and 14U.

In the evaporators 30 a to 30 n, a lower edge portion 68 a forming a lower side of the communication opening portion 68 in the back surface 45 is formed in a V-shape which is positioned on the upper side in the vertical direction from the center portion in the vehicle traveling direction toward a front side in the vehicle traveling direction, and is positioned on the upper side in the vertical direction from the center portion in the vehicle traveling direction toward the rear side in the vehicle traveling direction (refer to FIG. 17).

Therefore, even if the vehicle traveling direction is inclined with respect to the horizontal direction, the liquid-phase refrigerant can be prevented from flowing out from the liquid storage 63 a of each evaporator through the communication opening portion 68.

Third Embodiment

In the second embodiment, an example in which the two coolers 14 are aligned in the vehicle traveling direction has been described, but instead, a third embodiment in which three coolers 14 are aligned in the vehicle traveling direction will be described with reference to FIGS. 18A, 18B, 19A, and 19B. Among the three coolers 14, one of two coolers located in front of the other of the two coolers in the traveling direction is defined as a first cooler, and the other cooler located on the front side in the traveling direction is defined as a second cooler. One inlet 14 a of the cooler 14 corresponding to the first cooler corresponds to a first refrigerant inlet, and the other inlet 14 a of the cooler 14 corresponding to the second cooler corresponds to a second refrigerant inlet.

The present embodiment differs from the second embodiment in a battery cooling structure in which the secondary batteries 12 a and 12 b are cooled with the use of the cooler 14. For that reason, the battery cooling structure of the battery cooling unit 10 will be described below, and a description of the other components will be omitted.

The battery cooling unit 10 according to the present embodiment includes three coolers 14 and three pairs of secondary batteries 12 a and 12 b as the battery cooling structure.

The three coolers 14 are aligned in the vehicle traveling direction. The three coolers 14 are configured in the same manner as the cooler 14 of the first embodiment.

The three coolers 14 are aligned such that a stacking direction of evaporators 30 a to 30 m coincides with the vehicle traveling direction. In other words, in each of the coolers 14M and 14U, a refrigerant supply flow channel 70 extends in the vehicle traveling direction.

Hereinafter, for convenience of description, a cooler located on a front side of the three coolers 14 in the vehicle traveling direction is referred to as a cooler 14M, a cooler located on the rear side of the two coolers 14 in the vehicle traveling direction is referred to as a cooler 14U, and a cooler located between the coolers 14M and 14U is referred to as a cooler 14N.

The respective inlets 14 a of the coolers 14M, 14N, and 14U are provided on the front side in the vehicle traveling direction. The outlets 14 c of the coolers 14M, 14N, and 14U are provided on the rear side in the vehicle traveling direction.

The refrigerant outlets 14 c communicate with respective refrigerant supply flow channels 70 of the coolers 14M, 14N, and 14U.

The outlet 14 c of the cooler 14M and the inlet 14 a of the cooler 14N are connected to each other by a refrigerant pipe 81. The refrigerant pipe 81 configures a refrigerant flow channel for guiding the liquid-phase refrigerant from the outlet 14 c of the cooler 14M to the inlet 14 a of the cooler 14N.

The outlet 14 c of the cooler 14N and the inlet 14 a of the cooler 14U are connected to each other by a refrigerant pipe 82. The refrigerant pipe 82 configures a refrigerant flow channel for guiding the liquid-phase refrigerant from the outlet 14 c of the cooler 14N to the inlet 14 a of the cooler 14U.

The cooler 14M is disposed between a pair of secondary batteries 12 a and 12 b. The pair of secondary batteries 12 a and 12 b are aligned in the vehicle width direction across the cooler 14M. The inlet 14 a of the cooler 14M and the inlet 14 a of the cooler 14N are connected to each other by a bypass pipe 83 while bypassing the refrigerant supply flow channel 70 of the cooler 14M.

The bypass pipe 83 configures a refrigerant flow channel for guiding the liquid-phase refrigerant from the condenser 16 to the inlet 14 a of the cooler 14N by bypassing the refrigerant supply flow channel 70 of the cooler 14M.

The bypass pipe 83 is provided with an on-off valve 90. The on-off valve 90 selectively opens and closes the refrigerant flow channel of the bypass pipe 83 in accordance with the inclination of the vehicle (that is, the coolers 14M, 14N, and 14U).

The cooler 14N is disposed between the pair of secondary batteries 12 a and 12 b. The pair of secondary batteries 12 a and 12 b are aligned in the vehicle width direction across the cooler 14N. The inlet 14 a of the cooler 14N and the inlet 14 a of the cooler 14U are connected to each other by a bypass pipe 84 while bypassing the refrigerant supply flow channel 70 of the cooler 14N.

The bypass pipe 84 configures a refrigerant flow channel for guiding the liquid-phase refrigerant flowing in from the condenser 16 through the bypass pipe 83 to the inlet 14 a of the cooler 14U by bypassing the refrigerant supply flow channel 70 of the cooler 14N.

The bypass pipe 84 is provided with an on-off valve 91. The on-off valve 91 opens and closes the refrigerant flow channel of the bypass pipe 84 in accordance with the inclination of the vehicle (that is, the coolers 14M, 14N, and 14U).

As shown in FIG. 20, each of the on-off valves 90 and 91 according to the present embodiment includes a valve case 92 and a valve body 93 housed in the valve case 92.

In the valve case 92, flow channel openings 92 a and 92 b that configure a refrigerant flow channel between the refrigerant outlet of the condenser 16 and the inlet 14 a of the cooler 14N (or the cooler 14U) are provided.

The flow channel opening 92 a is disposed on the front side of the flow channel opening 92 b in the vehicle traveling direction. The valve body 93 is formed in a spherical shape, and closes one of the flow channel openings 92 a and 92 b in accordance with the inclination of the vehicle. As a result, the on-off valves 90 and 91 open and close the refrigerant flow channel between the refrigerant outlet of the condenser 16 and the inlet 14 a of the cooler 14N (or the cooler 14U) in accordance with the inclination of the vehicle.

Next, the operation of the battery cooling unit 10 according the present embodiment will be described.

First, when the vehicle traveling direction and the vehicle width direction of the vehicle coincide with the horizontal direction and the coolers 14M, 14N, and 14U assume the reference posture, the valve body 93 is positioned between the flow channel openings 92 a and 92 b in the on-off valves 90 and 91. For that reason, the flow channel openings 92 a and 92 b are opened by the valve body 93. Therefore, the on-off valves 90 and 91 are opened, respectively (refer to FIGS. 18A and 19A).

In that case, a part of the liquid-phase refrigerant from the condenser 16 flows into the refrigerant supply flow channel 70 through the inlet 14 a of the cooler 14M. For that reason, the liquid-phase refrigerant is sequentially supplied to respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14M.

In the liquid-phase refrigerant from the condenser 16, the remaining liquid-phase refrigerant other than a part of the liquid-phase refrigerant flowing into the cooler 14M passes through the bypass pipe 83 and the on-off valve 90. A part of the passed liquid-phase refrigerant flows into the refrigerant supply flow channel 70 through the inlet 14 a of the cooler 14N. For that reason, the liquid-phase refrigerant is sequentially supplied to the respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14N.

In the liquid-phase refrigerant that has passed through the bypass pipe 83 and the on-off valve 90, the remaining liquid-phase refrigerant other than the liquid-phase refrigerant that has flowed into the cooler 14N passes through the bypass pipe 84 and the on-off valve 91 and flows into the cooler 14U. For that reason, the liquid-phase refrigerant is sequentially supplied to the respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14U.

For that reason, each of the evaporators 30 a to 30 n of the coolers 14M, 14N, and 14U operates in the same manner as in the first embodiment. For that reason, the three pairs of secondary batteries 12 a and 12 b can be cooled by the coolers 14M, 14N, and 14U.

When the vehicle traveling direction is inclined with respect to the horizontal direction, for example, when the vehicle is climbing an uphill, the coolers 14M, 14N, and 14U are angled with respect to the reference posture. In that case, in the on-off valves 90 and 91, the flow channel opening of the flow channel openings 92 a and 92 b is closed by the valve body 93. For that reason, the on-off valves 90 and 91 are closed (refer to FIGS. 18B and 19B).

In that case, the liquid-phase refrigerant from the condenser 16 flows into the refrigerant supply flow channel 70 through the inlet 14 a of the cooler 14M. For that reason, the liquid-phase refrigerant is sequentially supplied to respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14M.

The liquid-phase refrigerant having passed through the refrigerant supply flow channel 70 of the cooler 14M flows through the refrigerant pipe 81 into the inlet 14 a of the cooler 14N. For that reason, the liquid-phase refrigerant flows into the refrigerant supply flow channel 70 of the cooler 14N. For that reason, the liquid-phase refrigerant is sequentially supplied to the respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14N.

The liquid-phase refrigerant having passed through the refrigerant supply flow channel 70 of the cooler 14N flows into the inlet 14 a of the cooler 14U through the refrigerant pipe 82. For that reason, the liquid-phase refrigerant flows into the refrigerant supply flow channel 70 of the cooler 14U. For that reason, the liquid-phase refrigerant is sequentially supplied to the respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14U.

For that reason, each of the evaporators 30 a to 30 n of the coolers 14M, 14N, and 14U operates in the same manner as in the first embodiment. For that reason, the three pairs of secondary batteries 12 a and 12 b can be cooled by the coolers 14M, 14N, and 14U.

According to the present embodiment described above, when the coolers 14M, 14N, and 14U assume the reference posture, the on-off valves 90 and 91 are in the open state. For that reason, the refrigerant supply flow channels 70 of the coolers 14M, 14N, and 14U are connected in parallel to the outward pipe 18. For that reason, a large amount of liquid-phase refrigerant can be supplied from the condenser 16 to the coolers 14M, 14N, and 14U.

In this example, when the coolers 14M, 14N, and 14U are inclined with respect to the reference posture, a large amount of the liquid-phase refrigerant flows into the cooler located at the lowest side among the coolers 14M, 14N, and 14U. For that reason, a deviation occurs in the amount of the liquid-phase refrigerant supplied to the coolers 14M, 14N, and 14U. Therefore, there is a possibility that a dry portion in which the liquid-phase refrigerant is insufficient is generated in the coolers 14M, 14N, and 14U.

Therefore, in the present embodiment, when the coolers 14M, 14N, and 14U are inclined with respect to the reference posture, the on-off valves 90 and 91 are in the closed state (refer to FIG. 20B). For that reason, the refrigerant supply flow channels 70 of the coolers 14M, 14N, and 14U are connected in series to the outward pipe 18. This makes it possible to reduce the deviation of the supply amount of the liquid-phase refrigerant supplied from the condenser 16 to the coolers 14M, 14N, and 14U. This makes it difficult for the coolers 14M, 14N, and 14U to generate a dry portion in which the liquid-phase refrigerant is insufficient.

When the coolers 14M, 14N, and 14U are inclined with respect to the reference posture, the refrigerant supply flow channels 70 of the coolers 14M, 14N, and 14U are connected in series with the outward pipe 18. For that reason, the supply amount of the liquid-phase refrigerant supplied from the condenser 16 to the coolers 14M, 14N, and 14U is reduced as compared with the case where the refrigerant supply flow channels 70 of the coolers 14M, 14N, and 14U are connected in parallel.

Therefore, in the present embodiment, a refrigerant control process of the electronic control device 200 according to a fifth embodiment to be described later may be performed to increase a condensing capacity of the condenser 16, thereby compensating for the decrease in the supply amount of the liquid-phase refrigerant supplied from the condenser 16 to the coolers 14M, 14N, and 14U.

Fourth Embodiment

In the third embodiment, an example in which the battery cooling unit 10 is configured with the use of three coolers 14 has been described, but instead, a fourth embodiment in which the battery cooling unit 10 is configured with the use of four coolers 14 will be described with reference to FIG. 20.

The present embodiment differs from the third embodiment in a battery cooling structure in which the secondary batteries 12 a and 12 b are cooled with the use of the cooler 14. For that reason, the battery cooling structure of the battery cooling unit 10 will be described below, and a description of the other components will be omitted.

The battery cooling unit 10 according to the present embodiment includes four coolers 14 and four pairs of secondary batteries 12 a and 12 b as the battery cooling structure.

The four coolers 14 are respectively configured in the same manner as the cooler 14 of the first embodiment. The four coolers 14 are aligned in a vehicle traveling direction. Hereinafter, for the sake of convenience of description, a cooler located on the most front side in the vehicle traveling direction among the four coolers 14 is referred to as a cooler 14M, and a cooler located on the most rear side in the vehicle traveling direction among the four coolers 14 is referred to as a cooler 14U.

The coolers 14M and 14U are disposed such that a stacking direction of evaporators 30 a to 30 m coincides with a vehicle width direction.

In other words, in each of the coolers 14M and 14U, a refrigerant supply flow channel 70 extends in a vehicle width direction (that is, in a direction intersecting with the vehicle traveling direction).

Among the four coolers 14, a cooler disposed between the coolers 14M and 14U is referred to as a cooler 14N, and among the four coolers 14, a cooler disposed between the coolers 14N and 14U is referred to as a cooler 14Q.

The respective inlets 14 a of the coolers 14M and 14Q are provided on one side of the refrigerant supply flow channel 70 in the vehicle width direction. Respective outlets 14 c of the coolers 14M and 14Q are provided on the other side of the refrigerant supply flow channel 70 in the vehicle width direction.

Respective inlets 14 a of the coolers 14N and 14U are provided on the other side of the refrigerant supply flow channel 70 in the vehicle width direction. In each of the coolers 14M and 14Q, an inlet/outlet 14 d is provided on one side of the refrigerant supply flow channel 70 in the vehicle width direction. The inlet/outlet 14 d is an inlet/outlet that serves as both a refrigerant inlet and a refrigerant outlet of the refrigerant supply flow channel 70.

The outlet 14 c of the cooler 14M and the inlet 14 a of the cooler 14N are connected to each other by a refrigerant pipe 100 as a communication flow channel forming member. The refrigerant pipe 100 configures a refrigerant flow channel for guiding the liquid-phase refrigerant from the outlet 14 c of the cooler 14M to the inlet 14 a of the cooler 14N.

The cooler 14M is disposed between a pair of secondary batteries 12 a and 12 b. The pair of secondary batteries 12 a and 12 b are aligned in the vehicle traveling direction across the cooler 14M.

The inlet 14 a of the cooler 14M and the inlet/outlet 14 d of the cooler 14N are connected to each other by bypassing the coolers 14M and 14N by a bypass pipe 101 as a bypass flow channel forming member. The bypass pipe 101 configures a refrigerant flow channel for supplying the liquid-phase refrigerant from the condenser 16 to the outlet/inlet 14 d of the cooler 14N by bypassing the coolers 14M and 14N. The bypass pipe 101 is provided with an on-off valve 90 for opening and closing the refrigerant flow channel of the bypass pipe 101.

The cooler 14N is disposed between the pair of secondary batteries 12 a and 12 b. The pair of secondary batteries 12 a and 12 b are aligned in the vehicle traveling direction across the cooler 14N.

The inlet/outlet 14 d of the cooler 14N and the inlet 14 a of the cooler 14Q are connected to each other by a refrigerant pipe 102 as a communication flow channel forming member. The refrigerant pipe 102 configures a refrigerant flow channel for guiding the liquid-phase refrigerant from the bypass pipe 101 and the inlet/outlet 14 d of the cooler 14N to the inlet 14 a of the cooler 14Q.

The cooler 14Q is disposed between the pair of secondary batteries 12 a and 12 b. The pair of secondary batteries 12 a and 12 b are aligned in the vehicle traveling direction across the cooler 14Q.

The outlet 14 c of the cooler 14Q and the inlet 14 a of the cooler 14U are connected to each other by a refrigerant pipe 103 as a communication flow channel forming member. The refrigerant pipe 103 configures a refrigerant flow channel for guiding the liquid-phase refrigerant from the outlet 14 c of the cooler 14Q to the inlet 14 a of the cooler 14U.

The inlet 14 a of the cooler 14Q and the inlet/outlet 14 d of the cooler 14U are connected to each other by a bypass pipe 104 as a bypass flow channel forming member. The bypass pipe 104 configures a refrigerant flow channel for guiding the liquid-phase refrigerant from the refrigerant pipe 102 to the outlet/inlet 14 d of the cooler 14N by bypassing the coolers 14Q and 14U.

The bypass pipe 104 is provided with an on-off valve 91 for opening and closing the refrigerant flow channel of the bypass pipe 104.

The cooler 14U is disposed between the pair of secondary batteries 12 a and 12 b. The pair of secondary batteries 12 a and 12 b are aligned in the vehicle traveling direction across the cooler 14U.

The on-off valves 90 and 91 according to the present embodiment are configured in the same manner as the on-off valves 90 and 91 of the third embodiment.

Next, the operation of the battery cooling unit 10 according the present embodiment will be described.

First, when the vehicle traveling direction and the vehicle width direction of the vehicle coincide with the horizontal direction, and the coolers 14M, 14N, 14Q, and 14U are in the reference posture, the on-off valves 90 and 91 are respectively in the open state (refer to FIG. 20A).

In that case, a part of the liquid-phase refrigerant from the condenser 16 flows into the refrigerant supply flow channel 70 through the inlet 14 a of the cooler 14M. For that reason, the liquid-phase refrigerant is sequentially supplied to respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14M.

The liquid-phase refrigerant other than a part of the liquid-phase refrigerant flowing into the cooler 14M out of the liquid-phase refrigerant from the condenser 16 passes through the bypass pipe 101 and the on-off valve 90. A part of the passed liquid-phase refrigerant flows into the refrigerant supply flow channel 70 through the inlet 14 a of the cooler 14N. For that reason, the liquid-phase refrigerant is sequentially supplied to the respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14N.

Of the liquid-phase refrigerant that has passed through the bypass pipe 83 and the on-off valve 90, the remaining liquid-phase refrigerant other than the liquid-phase refrigerant that has flowed into the cooler 14N passes through the refrigerant pipe 102. A part of the liquid-phase refrigerant that has passed through the refrigerant pipe 102 flows into the inlet 14 a of the cooler 14Q. For that reason, the liquid-phase refrigerant is sequentially supplied to the respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14Q.

The remaining liquid-phase refrigerant other than the part of the liquid-phase refrigerant that has flowed into the cooler 14Q in the liquid-phase refrigerants that have passed through the refrigerant pipe 102 flows into the inlet/outlet 14 d of the cooler 14U. For that reason, the liquid-phase refrigerant is sequentially supplied to the respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14U.

For that reason, the respective evaporators 30 a to 30 n of the coolers 14M, 14N, 14Q, and 14U operate in the same manner as in the first embodiment. For that reason, the four pairs of secondary batteries 12 a and 12 b can be cooled by the coolers 14M, 14N, 14Q, and 14U.

When the vehicle traveling direction is inclined with respect to the horizontal direction, for example, when the vehicle is climbing an uphill, the coolers 14M, 14N, 14Q, and 14U are inclined with respect to the reference posture. In that case, the on-off valves 90 and 91 are closed.

In that case, the liquid-phase refrigerant from the condenser 16 flows into the refrigerant supply flow channel 70 through the inlet 14 a of the cooler 14M. For that reason, the liquid-phase refrigerant is sequentially supplied to respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14M.

The liquid-phase refrigerant having passed through the refrigerant supply flow channel 70 of the cooler 14M flows through the refrigerant pipe 100 into the inlet 14 a of the cooler 14N. For that reason, the liquid-phase refrigerant flows into the refrigerant supply flow channel 70 of the cooler 14N. For that reason, the liquid-phase refrigerant is sequentially supplied to the respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14N.

The liquid-phase refrigerant having passed through the refrigerant supply flow channel 70 of the cooler 14N flows through the refrigerant pipe 102 into the inlet 14 a of the cooler 14Q. For that reason, the liquid-phase refrigerant flows into the refrigerant supply flow channel 70 of the cooler 14Q. For that reason, the liquid-phase refrigerant is sequentially supplied to the respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14Q.

Thereafter, the liquid-phase refrigerant having passed through the refrigerant supply flow channel 70 of the cooler 14Q flows into the inlet 14 a of the cooler 14U through the refrigerant pipe 103. For that reason, the liquid-phase refrigerant flows into the refrigerant supply flow channel 70 of the cooler 14U. For that reason, the liquid-phase refrigerant is sequentially supplied to the respective liquid storages 63 a of the evaporators 30 a to 30 n of the cooler 14U.

For that reason, the respective evaporators 30 a to 30 n of the coolers 14M, 14N, 14Q, and 14U operate in the same manner as in the first embodiment. For that reason, the three pairs of secondary batteries 12 a and 12 b can be cooled by the coolers 14M, 14N, 14Q, and 14U.

According to the present embodiment described above, when the coolers 14M, 14N, 14Q, and 14U are in the reference posture, the on-off valves 90 and 91 are in the open state. For that reason, the refrigerant supply flow channels 70 of the coolers 14M, 14N, and 14U are connected in parallel to the outward pipe 18.

When the coolers 14M, 14N, and 14U are inclined with respect to the reference posture, the on-off valves 90 and 91 are closed. For that reason, the refrigerant supply flow channels 70 of the coolers 14M, 14N, and 14U are connected in series to the outward pipe 18.

Therefore, similarly to the third embodiment, the deviation of the supply amount of the liquid-phase refrigerant supplied from the condenser 16 to the coolers 14M, 14N, and 14U can be reduced. This makes it difficult for the coolers 14M, 14N, and 14U to generate a dry portion in which the liquid-phase refrigerant is insufficient.

Fifth Embodiment

In a fifth embodiment, an example will be described in which, in the battery cooling unit 10 of the first embodiment, a control is performed to increase the supply amount of liquid-phase refrigerant from a condenser 16 to a cooler 14 in accordance with the inclination of a vehicle or the like.

FIG. 21 shows an overall configuration of a battery cooling unit 10 according to the present embodiment.

In the battery cooling unit 10 according to the present embodiment, an electronic control device 200, an electric fan 215, a current sensor 213, and a tilt sensor 214 are added to the battery cooling unit 10 of the first embodiment.

The electronic control device 200 includes a processor 200 a, a memory, and the like, and executes a refrigerant control process in accordance with a computer program stored in advance in the memory. The electronic control device 200 (i.e., the processor 200 a) controls an electric fan 215 in accordance with a detection value of a current sensor 213 and a detection value of a tilt sensor 214 with the execution of a refrigerant control process. The memory is a non-transitory tangible storage medium.

The current sensor 213 detects a current flowing from secondary batteries 12 a and 12 b to an inverter circuit (that is, the electric motor). The tilt sensor 214 detects an inclination angle in a vehicle width direction with respect to a horizontal direction and an inclination angle in a vehicle traveling direction with respect to the horizontal direction. The electric fan 215 generates an air flow as a heat receiving fluid passing through the condenser 16.

Next, a refrigerant control process executed by the processor 200 a of the electronic control device 200 according to the present embodiment will be described.

The processor 200 a of the electronic control device 200 executes a refrigerant control process according to a flowchart of FIG. 22. The electronic control device 200 repeatedly executes the refrigerant control process.

First, in Step 100 (that is, the determination unit), the electronic control device 200 determines whether or not the vehicle is inclined in accordance with the detection value of the tilt sensor 214. When the vehicle width direction is inclined with respect to the horizontal direction, or when the vehicle traveling direction is inclined with respect to the horizontal direction, it is determined that the cooler 14 is angled with respect to the reference posture, and the electronic control device 200 makes the determination of YES in Step 100.

Next, in Step 110, the electronic control device 200 determines whether or not the secondary batteries 12 a and 12 b generate a heat in accordance with the detection value of the current sensor 213.

When the current flowing from the secondary batteries 12 a and 12 b into the inverter circuit is equal to or larger than a threshold, the electronic control device 200 makes the determination of YES in Step 110 that the secondary batteries 12 a and 12 b generate the heat.

In that case, in Step 120, the electronic control device 200 controls the electric fan 215 as a refrigerant increasing unit to increase the volume of air flow passing through the condenser 16, thereby improving the cooling performance for condensing the gas-phase refrigerant in the condenser 16.

As a result, the amount of heat radiated from the gas-phase refrigerant in the condenser 16 to the air flow increases. Therefore, the amount of refrigerant condensed in the condenser 16 increases. As a result, the supply amount of the liquid-phase refrigerant supplied from the condenser 16 to the cooler 14 increases.

Thereafter, the process returns to Step 100, and when the electronic control device 200 makes the determination of YES that the vehicle is inclined, the process proceeds to Step 110. At that time, when the current flowing from the secondary batteries 12 a and 12 b into the inverter circuit is less than the threshold, the electronic control device 200 makes the determination of NO that the secondary batteries 12 a and 12 b do not generate a heat in Step 110.

In that case, in Step 130, the electronic control device 200 controls the electric fan 215 to reduce the volume of the air flow passing through the condenser 16. For that reason, the amount of heat radiated from the gas-phase refrigerant in the condenser 16 to the air flow is reduced. For that reason, the amount of refrigerant condensed in the condenser 16 is reduced. Accordingly, the supply amount of the liquid-phase refrigerant supplied from the condenser 16 to the cooler 14 decreases.

When the vehicle width direction coincides with the horizontal direction and the vehicle traveling direction coincides with the horizontal direction in Step 100, the electronic control device 200 makes the determination of NO that the cooler 14 is in the reference posture. In that case, the inclination determination in Step 100 is repeated.

According to the present embodiment described above, when the electronic control device 200 determines that the cooler 14 is inclined with respect to the reference posture and determines that the secondary batteries 12 a and 12 b generate a heat, the electronic control device 200 controls the electric fan 215 to increase the volume of the air flow passing through the condenser 16.

Therefore, the supply amount of the liquid-phase refrigerant supplied from the condenser 16 to the cooler 14 can be increased.

In this example, in the conventional battery cooling unit 10 that does not execute the refrigerant control process, if the liquid-phase refrigerant is continuously supplied to the evaporators 30 a to 30 m of the cooler 14 from an upstream side to a downstream side, dry portions are hardly generated in the evaporation flow channels 61 a and 61 b of each evaporator.

However, when the temperatures of the secondary batteries 12 a and 12 b as objects to be cooled are high and the supply of the liquid crystal refrigerant is small, the liquid-phase refrigerant may not be supplied to the upstream liquid storage 63 a and the liquid storage 63 a at the center of the downstream liquid storage 63 a depending on the setting of the liquid storage 63 a.

Alternatively, it is assumed that only the upstream evaporator consumes the liquid-phase refrigerant, so that the downstream evaporator dries out.

On the other hand, in the present embodiment, with an increase in the supply amount of the liquid-phase refrigerant to the cooler 14 by detecting the inclination of the vehicle and the secondary batteries (loads (temperatures) of objects to be cooled) 12 a and 12 b, the supply of the liquid-phase refrigerant increases at the time of inclination, the supply shortage of the liquid-phase refrigerant of the downstream evaporator can be avoided, and the generation of the high-temperature portion in the downstream evaporator can be avoided.

As described above, the heat radiation amount radiated from the secondary batteries 12 a and 12 b to the liquid-phase refrigerant can be increased. Accordingly, the secondary batteries 12 a and 12 b can be satisfactorily cooled.

Sixth Embodiment

In the first embodiment, an example in which the refrigerant supply flow channel 70 and the gas-phase refrigerant flow channel 71 are configured by the evaporators 30 a to 30 m in the cooler 14 has been described, but instead, a sixth embodiment in which a refrigerant supply flow channel 70 and a gas-phase refrigerant flow channel 71 are configured by two refrigerant pipes in a cooler 14 will be described with reference to FIGS. 23, 24A, 24B, and 24C.

Since the present embodiment differs from the first embodiment in the structure of the cooler 14, the cooler 14 of the present embodiment will be described below, and a description other than the cooler 14 will be omitted.

The cooler 14 according to the present embodiment includes multiple extrusion pipes 110, a refrigerant supply pipe 70A, and a gas-phase refrigerant pipe 71A.

The multiple extrusion pipes 110 are aligned in a vehicle traveling direction. The multiple extrusion pipes 110 are composite flow channels including multiple narrow tubes 110 a. The multiple narrow tubes 110 a are aligned in the vehicle traveling direction and are formed so as to extend in a vertical direction. The narrow tubes 110 a correspond to narrow flow channels.

Each of the multiple narrow tubes 110 a configures the evaporation flow channel 61 a of the first embodiment for evaporating the liquid-phase refrigerant by a heat exchange between the liquid-phase refrigerant from the refrigerant supply pipe 70A and the secondary battery 12 a.

A flow channel cross-sectional area of each of the multiple narrow tubes 110 a according to the present embodiment is smaller than a flow channel cross-sectional area of the refrigerant supply flow channel 70.

The refrigerant supply pipe 70A configures a refrigerant supply flow channel 70 for supplying the liquid-phase refrigerant from the condenser 16 to the multiple extrusion pipes 110. The refrigerant supply pipe 70A is formed to extend in the vehicle traveling direction. The refrigerant supply pipe 70A is disposed on a lower side of the multiple extrusion pipes 110 in the vertical direction.

The refrigerant supply pipe 70A is provided with multiple through holes 72 a which are opened to an upper side in the vertical direction and aligned in the vehicle traveling direction. A lower side of the corresponding extrusion pipe 110 among the multiple extrusion pipes 110 is inserted into each of the multiple through holes 72 a of the refrigerant supply pipe 70A.

In the present embodiment, the refrigerant inlet 64 a of each of the multiple narrow tubes 110 a is disposed below the center of the refrigerant supply flow channel 70 in the vertical direction.

However, when the position of the refrigerant supply flow channel 70 on the uppermost side in the vertical direction is defined as the uppermost position and the position of the refrigerant supply flow channel 70 on the lowermost side in the vertical direction is defined as the lowermost position, the center of the refrigerant supply flow channel 70 in the vertical direction is a middle between the uppermost portion and the lowermost portion.

The gas-phase refrigerant pipe 71A configures a gas-phase refrigerant flow channel 71 for collecting the gas-phase refrigerant from the multiple extrusion pipes 110 and allowing the collected gas-phase refrigerant to flow into the condenser 16. The gas-phase refrigerant pipe 71A is formed to extend in the vehicle traveling direction. The gas-phase refrigerant pipe 71A is disposed above the multiple extrusion pipes 110 in the vertical direction.

The gas-phase refrigerant pipe 71A is provided with multiple through holes 72 b which are opened to a lower side in the vertical direction and are aligned in the vehicle traveling direction. The upper side of the corresponding extrusion pipe 110 among the multiple extrusion pipes 110 is inserted into each of the multiple through holes 72 b of the gas-phase refrigerant pipe 71A.

The corresponding battery cell 13 of the multiple battery cells 13 of the secondary battery 12 a is in contact with each of the multiple extrusion pipes 110 according to the present embodiment.

Next, the operation of the cooler 14 according to the present embodiment will be described.

First, the liquid-phase refrigerant from the condenser 16 flows into the refrigerant supply flow channel 70 of the refrigerant supply pipe 70A. The liquid-phase refrigerant from the refrigerant supply flow channel 70 enters the multiple narrow tubes 110 a of each of the extrusion pipes 110.

The secondary batteries 12 a and 12 b generate a heat, and the heat is transferred from the secondary battery 12 a to the multiple extrusion pipes 110.

Then, the liquid-phase refrigerant in the multiple narrow tubes 110 a for each of the extrusion pipes 110 boils.

As a result, the liquid-phase refrigerant in the multiple narrow tubes 110 a for each of the extrusion pipes 110 evaporates. For that reason, as the liquid-phase refrigerant boils, air bubbles containing the gas-phase refrigerant are generated from the inside of the liquid-phase refrigerant.

At that time, a volume of the liquid-phase refrigerant containing air bubbles in the multiple narrow tubes 110 a of the extrusion pipe 110 becomes larger than a volume of the liquid-phase refrigerant containing no air bubbles at the time of stopping the heat exchange. For that reason, a liquid surface of the liquid-phase refrigerant in the multiple narrow tubes 110 a rises above a liquid surface of the liquid-phase refrigerant at the time of vehicle stop.

In other words, in the multiple narrow tubes 110 a, the liquid surface of the liquid-phase refrigerant in the evaporation flow channels 61 a and 61 b rises due to the bubble pump effect in which the liquid-phase refrigerant containing the air bubbles rises as a bubble mixed flow.

At this time, the liquid-phase refrigerant is supplied to the upper side of the inside of the multiple narrow tubes 110 a in the vertical direction, and the liquid-phase refrigerant is evaporated by taking the heat of the secondary batteries 12 a and 12 b to obtain the gas-phase refrigerant. The gas-phase refrigerant flows into the condenser 16 through the gas-phase refrigerant pipe 71A.

In the present embodiment described above, the cooler 14 includes the multiple extrusion pipes 110 configuring an evaporator, and the inlets 64 a of the multiple narrow pipes 110 a are disposed on a lower side of the center of the refrigerant supply flow channel 70 in the vertical direction.

Therefore, even if the cooler 14 is inclined from the predetermined reference posture and the supply amount of the liquid-phase refrigerant from the condenser 16 to the cooler 14 is small, it is advantageous to arrange the liquid surface of the liquid-phase refrigerant above the refrigerant supply flow channel 70 as compared with the case where the refrigerant inlet 64 a is positioned above the center portion of the refrigerant supply flow channel 70 in the vertical direction.

For that reason, the liquid-phase refrigerant can be stably supplied from the refrigerant supply flow channel 70 to the multiple extrusion pipes 110. As a result, the secondary battery 12 a can be stably cooled by the liquid-phase refrigerant.

Seventh Embodiment

In a seventh embodiment, an example in which a liquid storage 63 a is provided for each extrusion pipe 110 in the refrigerant supply pipe 70A of the cooler 14 of the sixth embodiment will be described with reference to FIGS. 25A, 25B, and 25C.

In a refrigerant supply pipe 70A according to the present embodiment, a protrusion portion 120 convex to a lower side in a vertical direction is provided for each of extrusion pipes 110. The protrusion portion 120 of each extrusion pipe 110 forms a liquid storage 63 a recessed downward in the vertical direction from the refrigerant supply pipe 70A.

As a result, in the refrigerant supply pipe 70A, the liquid storage 63 a is formed for each of the extrusion pipes 110.

A refrigerant inlet 64 a of each of the multiple narrow tubes 110 a according to the present embodiment is disposed in the liquid storage 63 a on the lower side of the center of the refrigerant supply flow channel 70 in the vertical direction. For that reason, even if the supply amount of the liquid-phase refrigerant from the condenser 16 to the cooler 14 is small, it is more advantageous to dispose a liquid surface of the liquid-phase refrigerant above the refrigerant supply flow channel 70 as compared with the case where the refrigerant inlet 64 a is positioned above the center portion of the refrigerant supply flow channel 70 in the vertical direction.

Eighth Embodiment

In the seventh embodiment, an example in which the liquid storage 63 a is formed in the protrusion portion 120 of the refrigerant supply pipe 70A on the lower side in the vertical direction has been described, but instead, an eighth embodiment in which a liquid storage 63 a is formed by providing a weir portion 130 on a lower side of a refrigerant supply pipe 70A in the vertical direction for each of extrusion pipes 110 will be described with reference to FIGS. 26A, 26B, and 26C.

The weir portion 130 is formed so as to protrude upward in the vertical direction in the refrigerant supply pipe 70A. The weir portion 130 is disposed on a refrigerant flow downstream side of the extrusion pipe 110 for each of the extrusion pipes 110. For that reason, in the refrigerant supply pipe 70A, the multiple weir portions 130 are aligned in the refrigerant flow direction with an interval.

A space between two adjacent weir portions 130 among the multiple weir portions 130 configures a liquid storage 63 a recessed downward in the vertical direction from the refrigerant supply flow channel 70.

A refrigerant inlet 64 a of each of the multiple narrow tubes 110 a according to the present embodiment is disposed in the liquid storage 63 a on the lower side of the center of the refrigerant supply flow channel 70 in the vertical direction. For that reason, similarly to the seventh embodiment, it is more advantageous in disposing the liquid surface of the liquid-phase refrigerant above the refrigerant supply flow channel 70, as compared with the case where the refrigerant inlet 64 a is positioned above the center portion of the refrigerant supply flow channel 70 in the vertical direction.

OTHER EMBODIMENTS

(1) In the first to eighth embodiments described above, an example in which the secondary battery 12 is used as the object to be cooled has been described, but the present disclosure is not limited to the above configuration, and various devices other than the secondary battery 12, a semiconductor device, a gas such as air, and the like may be used as the object to be cooled.

(2) In the first to eighth embodiments, an example in which the cooler of the present disclosure is applied to the battery cooling unit 10 has been described, but the present disclosure is not limited to the above example, and the cooler may be applied to various moving bodys other than automobiles (trains, airplanes, electric motorcycles, etc.).

The thermosiphon of the present disclosure may be applied to a portable battery with a cooling function which can be carried out by combining a battery with a thermosiphon.

(3) In the first to eighth embodiments, an example has been described in which the lower edge portion 68 a forming the lower side of the communication opening portion 68 is formed in a V-shape in the back surface 45 of each of the evaporators 30 a to 30 m, but instead, the communication opening portion 68 of the back surface 45 may have any shape, may be circular, or may have a square shape.

(4) In the first to eighth embodiments, the lower surface 42, the partition walls 60 a and 60 b, and the back surface wall 69 form the liquid storage 63 a for each evaporator so as to correspond to the inclination in the four directions, but instead, the liquid storage 63 a for each evaporator may have any shape as long as the liquid storage 63 a corresponds to the inclination in at least one direction.

(5) In the first to eighth embodiments, an example in which the inlet 64 a (or 64 b) of the evaporation flow channel 61 a (or 61 b) communicates with the lower side of the liquid storage 63 a in the vertical direction has been described, but the present disclosure is not limited to the above configuration, and the following configuration may be used.

In other words, if the inlets 64 a and 64 b of the evaporation flow channels 61 a and 61 b are located on the vertical lower side of the center of the refrigerant supply flow channel 70 in the vertical direction, the inlet 64 a and 64 b of the evaporation flow channel 61 a and 61 b may communicate with each other at any location in the liquid storage 63 a. For example, the inlets 64 a and 64 b of the evaporation flow channels 61 a and 61 b may communicate with each other at the center of the liquid storage 63 a in the vertical direction.

(6) In the fifth embodiment, an example in which the gas-phase refrigerant in the condenser 16 is cooled by the air flow has been described, but instead, the gas-phase refrigerant in the condenser 16 may be cooled by a heat medium other than the air flow (for example, water, chlorofluorocarbon, carbon dioxide).

(7) In the fifth embodiment, the cooling performance of the gas-phase refrigerant of the condenser 16 is improved by increasing the volume of air passing through the condenser 16, but the cooling performance of the gas-phase refrigerant of the condenser 16 may be improved by the following configurations (7a), (7b), or (7c). (7a) The temperature of the air flow passing through the condenser 16 is reduced to improve the cooling performance of the gas-phase refrigerant in the condenser 16. (7b) When the gas-phase refrigerant in the condenser 16 is cooled by a heat medium (for example, water, chlorofluorocarbon, carbon dioxide) other than the air flow, the flow rate of the heat medium passing through the condenser 16 is increased or the temperature of the heat medium passing through the condenser 16 is lowered. (7c) A cooling element such as a Peltier element cools the gas-phase refrigerant in the condenser 16 to improve the cooling performance of the gas-phase refrigerant in the condenser 16.

(8) In the fifth embodiment, an example in which the cooling performance of the gas-phase refrigerant in the condenser 16 is improved to increase the supply amount of the liquid-phase refrigerant from the condenser 16 to the cooler 14 in Step 120 has been described, but the following configurations (8a) or (8b) may be used instead of above configuration. (8a) The amount of the liquid-phase refrigerant supplied from the condenser 16 to the cooler 14 may be increased by increasing the amount of heat generated by the secondary batteries 12 a and 12 b to increase the amount of evaporation of the refrigerant in the cooler 14. Specifically, the current flowing from the secondary batteries 12 a and 12 b to the inverter circuit is increased, whereby the heat generation amount of the secondary batteries 12 a and 12 b is increased. (8b) The liquid-phase refrigerant is heated by heaters or Peltier elements, with the result that the supply amount of the liquid-phase refrigerant supplied from the condenser 16 to the cooler 14 is increased.

(9) In the fifth embodiment, an example has been described in which the electronic control device 200 determines whether or not the secondary batteries 12 a and 12 b generate the heat in accordance with the detection value of the current sensor 213 in Step 110, but the following configurations (9a) or (9b) may be adopted instead of the above example. (9a) The electronic control device 200 may determine whether or not the secondary batteries 12 a and 12 b generate a heat in accordance with the detection value of the temperature sensor that detects the temperatures of the secondary batteries 12 a and 12 b. (9b) The electronic control device 200 may detect a temperature distribution of the secondary batteries 12 a and 12 b and determine whether or not the secondary batteries 12 a and 12 b generate a heat in accordance with the temperature distribution.

(10) In the fifth embodiment, an example has been described in which the electronic control device 200 determines whether or not the cooler 14 is inclined in accordance with the detection value of the tilt sensor 214 in Step 100.

In other words, the electronic control device 200 may detect the temperature distribution of the secondary batteries 12 a and 12 b and determine whether or not the cooler 14 is inclined in accordance with the temperature distribution.

(11) In the first embodiment, an example in which the heat conduction materials 170 a and 170 b are disposed between a laminated heat exchanger 160 and the secondary battery 12 a has been described, but the present disclosure is not limited to the above configuration, and if the secondary battery 12 a has electrical insulation properties, there is no need to dispose the heat conduction materials 170 a and 170 b between the laminated heat exchanger 160 and the secondary batteries 12 a and 12 b.

(12) In the first embodiment, an example in which the evaporators 30 a to 30 m are configured for each of the battery cells 121 in the cooler 14 has been described, but the present disclosure is not limited to the above configuration, and the evaporators 30 a to 30 m need only be formed for each section, and the evaporators 30 a to 30 m need not be configured for each of the battery cells 121.

(13) In the first embodiment, an example in which the two evaporation flow channels 61 a and 61 b are provided in each of the evaporators 30 a to 30 m in the cooler 14 has been described, but instead, one evaporation flow channel or three or more evaporation flow channels may be provided in each of the evaporators 30 a to 30 m.

(14) In the first embodiment, an example in which twelve liquid storage/evaporators such as the evaporators 30 a to 30 m are provided has been described, but the number of evaporators is not limited to twelve, and may be any number, one or a plurality other than twelve.

(15) The battery cooling unit 10 may be configured by combining two or more embodiments that can be combined among the first to eighth embodiments. For example, the battery cooling unit 10 may be configured by combining two or more embodiments as in the following configurations (15a) to (15d). (15a) The battery cooling unit 10 may be configured by combining the refrigerant control process of the electronic control device 200 according to the fifth embodiment with the battery cooling unit 10 of any one of the second to fourth embodiments. (15b) The battery cooling unit 10 may be configured by employing the cooler 14 of the sixth embodiment in any one of the first to fifth embodiments. (15c) In any one of the first to fifth embodiments, the cooler 14 of the seventh embodiment may be employed to configure the battery cooling unit 10. (15d) In any one of the first to fifth embodiments, the cooler 14 of the eighth embodiment may be employed to configure the battery cooling unit 10.

(16) In the first embodiment, an example in which the evaporators 30 a to 30 m are aligned in the vehicle traveling direction has been described, but the present disclosure is not limited to the above configuration, and the evaporators 30 a to 30 m may be aligned in a direction intersecting with the vehicle traveling direction.

(17) In the second embodiment, an example in which the coolers 14M and 14U are aligned in the vehicle traveling direction has been described, but the present disclosure is not limited to the above configuration, and the coolers 14M and 14U may be aligned in a direction intersecting with the vehicle traveling direction.

(18) In the second embodiment, an example in which the evaporators 30 a to 30 m are aligned in the vehicle width direction has been described, but the present disclosure is not limited to the above configuration, and the evaporators 30 a to 30 m may be aligned in a direction intersecting with the vehicle width direction.

(19) In the third embodiment, an example in which the coolers 14M, 14N, and 14U are aligned in the vehicle traveling direction has been described, but the present disclosure is not limited to the above configuration, and the coolers 14M, 14N, and 14U may be aligned in a direction intersecting with the vehicle traveling direction.

(20) In the third embodiment, an example in which the evaporators 30 a to 30 m are aligned in the vehicle traveling direction has been described, but the present disclosure is not limited to the above configuration, and the evaporators 30 a to 30 m may be aligned in a direction intersecting with the vehicle traveling direction.

(21) In the third embodiment, an example in which three coolers are aligned has been described, but the present disclosure is not limited to the above configuration, and two coolers or four or more coolers may be aligned.

(22) In the fourth embodiment, an example in which the coolers 14M, 14N, 14Q, and 14U are aligned in the vehicle traveling direction has been described, but the present disclosure is not limited to the above configuration, and the coolers 14M, 14N, 14Q, and 14U may be aligned in the direction intersecting with the vehicle traveling direction.

(23) In the fourth embodiment, an example in which the evaporators 30 a to 30 m are aligned in the vehicle width direction has been described, but the present disclosure is not limited to the above configuration, and the evaporators 30 a to 30 m may be aligned in a direction intersecting with the vehicle width direction.

(24) In the fourth embodiment, an example in which four coolers are aligned has been described, but the present disclosure is not limited to the above configuration, and two coolers, three coolers, or five or more coolers may be aligned.

(25) In the third and fourth embodiments described above, an example has been described in which the on-off valves 90 and 91 are opened and closed by using the valve body 93 that moves by gravity.

In other words, the on-off valves 90 and 91 are configured with the use of an electromagnetic valve or an electrically operated valve. The electronic control device opens and closes the on-off valves 90 and 91 in accordance with the detection value of the tilt sensor for detecting the inclination of the vehicle (that is, the cooler).

(26) In the first, second, third, and fourth embodiments, an example in which the two secondary batteries 12 a and 12 b are cooled for each cooler by the cooler 14 (14M, 14N, 14U) has been described, but instead, one secondary battery may be cooled for each cooler by the cooler 14 (14M, 14N, 14U).

(27) In the first to eighth embodiments, an example in which the condenser 16 is disposed on the front side of the cooler 14 (14M, 14N, 14U) in the vehicle traveling direction has been described. Instead, the following configurations may be applied.

In other words, if the condenser 16 is disposed above the cooler 14 (14M, 14N, 14U) in the vertical direction when the vehicle is inclined, the condenser 16 may be disposed on the rear side of the cooler 14 (14M, 14N, 14U) in the vehicle traveling direction.

(28) In the first to fifth embodiments, an example in which the evaporators 30 a to 30 m are connected in series with each other has been described, but the present disclosure is not limited to the above configuration, and some of the evaporators 30 a to 30 m may be connected in parallel.

In this example, if the number of evaporators connected in parallel is small, the distribution of the liquid-phase refrigerant to the evaporators connected in parallel can be performed satisfactorily, so that the temperature distribution occurring in the secondary batteries 12 a and 12 b becomes satisfactory.

(29) In the fifth embodiment, an example has been described in which the electronic control device 200 determines that the cooler 14 is in the reference posture when the vehicle width direction coincides with the horizontal direction and the vehicle traveling direction coincides with the horizontal direction, but instead, the following configurations may be applied.

In other words, when an angle formed between the horizontal direction and the vehicle width direction is less than a first threshold and an angle formed between the horizontal direction and the vehicle traveling direction is less than a second threshold, the electronic control device 200 determines that the cooler 14 is in the reference posture.

The electronic control device 200 determines that the cooler 14 is inclined with respect to the reference posture when the angle formed between the horizontal direction and the vehicle width direction is equal to or greater than the first threshold, or when the angle formed between the horizontal direction and the vehicle traveling direction is equal to or greater than the second threshold.

In this manner, it may be determined whether or not the cooler 14 is in the reference posture in consideration of a slight error in the determination of the inclination angle.

In the third and fourth embodiments, the electronic control device determines whether or not the cooler 14 is in the reference posture in consideration of a slight error in the inclination angle based on the detection value of the tilt sensor that detects the inclination of the cooler.

When the electronic control device determines that the cooler 14 is in the reference posture, the electronic control device opens the on-off valves 90 and 91. When the electronic control device determines that the cooler 14 is inclined from the reference posture, the electronic control device closes the on-off valves 90 and 91.

(30) In the first to eighth embodiments, the liquid-phase refrigerant flows from the front side in the vehicle traveling direction to the rear side in the vehicle traveling direction in the cooler 14 (14M, 14N, 14Q, 14U), but the present disclosure is not limited to the above configuration, and the liquid-phase refrigerant may flow from the rear side in the vehicle traveling direction to the front side in the vehicle traveling direction in the cooler 14 (14M, 14N, 14Q, 14U).

(31) It should be noted that the present disclosure is not limited to the above-described embodiments, and can be modified as appropriate. The above embodiments are not independent of each other, and can be appropriately combined except when the combination is obviously impossible. Further, in each of the above-mentioned embodiments, it goes without saying that components of the embodiment are not necessarily essential except for a case in which the components are particularly clearly specified as essential components, a case in which the components are clearly considered in principle as essential components, and the like. Further, in each of the embodiments described above, when numerical values such as the number, numerical value, quantity, range, and the like of the constituent elements of the embodiment are referred to, except in the case where the numerical values are expressly indispensable in particular, the case where the numerical values are obviously limited to a specific number in principle, and the like, the present disclosure is not limited to the specific number. Further, in each of the above-mentioned embodiments, when referring to the shape, positional relationship, and the like of a component and the like, the component is not limited to the shape, positional relationship, and the like, except for the case where the component is specifically specified, the case where the component is fundamentally limited to a specific shape, positional relationship, and the like.

(Overview)

According to a first aspect described in part or all of the first to eighth embodiments and the other embodiments, there is provided a cooler that configures a thermosiphon which circulates a refrigerant together with a condenser which condenses a gas-phase refrigerant and discharges a liquid-phase refrigerant, the cooler including: a first flow channel forming member that provides a supply flow channel through which the liquid-phase refrigerant from the condenser flows; a second flow channel forming member that provides an evaporation flow channel which includes a refrigerant inlet communicating with the supply flow channel, and is configured to extend upward from the refrigerant inlet, and evaporates the liquid-phase refrigerant by a heat exchange between the liquid-phase refrigerant flowing from the supply flow channel through the refrigerant inlet and an object to be cooled to generate the gas-phase refrigerant; and a third flow channel forming member that provides a discharge flow channel through which the gas-phase refrigerant from the evaporation flow channel flows toward the condenser, in which the refrigerant inlet is located on the lower side of a center portion of the supply flow channel in the vertical direction.

According to a second aspect, the refrigerant inlet is disposed on the lower side of the supply flow channel.

Therefore, even if the supply amount of the liquid-phase refrigerant from the condenser to the cooler is small, it is more advantageous in placing the liquid surface of the liquid-phase refrigerant above the refrigerant inlet as compared with the case where the refrigerant inlet is positioned above the center portion of the supply flow channel in the vertical direction.

According to a third aspect, one or more liquid storages formed so as to be recessed downward from the supply flow channel and storing the liquid-phase refrigerant from the supply flow channel are provided.

Therefore, the supply of the liquid-phase refrigerant to the evaporation flow channel can be stabilized.

According to a fourth aspect, there is provided a cooler that configures a thermosiphon which circulates a refrigerant together with a condenser which condenses a gas-phase refrigerant and discharges a liquid-phase refrigerant, the cooler including: a first flow channel forming member that provides a supply flow channel through which the liquid-phase refrigerant from the condenser flows; a second flow channel forming member that provides an evaporation flow channel which includes a refrigerant inlet into which the liquid-phase refrigerant from the supply flow channel flows, and evaporates the liquid-phase refrigerant by a heat exchange between the liquid-phase refrigerant flowing in through the refrigerant inlet and an object to be cooled to circulate the gas-phase refrigerant toward the condenser; a third flow channel forming member that provides a discharge flow channel through which the gas-phase refrigerant from the evaporation flow channel flows toward the condenser; and one or more liquid storages that are formed to be recessed downward from the supply flow channel to store the liquid-phase refrigerant from the supply flow channel, in which the refrigerant inlet communicates with the liquid storages and is located at the same height as a liquid surface of the liquid-phase refrigerant in the liquid storages, or located below the liquid surface.

According to a fifth aspect, the cooler includes a plurality of the evaporation flow channels aligned in a refrigerant flow direction of the supply flow channel, in which the one or more liquid storages comprises a plurality of liquid storages aligned in the refrigerant flow direction of the supply flow channel, and each of the plurality of liquid storages communicates with a refrigerant inlet of a corresponding one of the plurality of the evaporation flow channels.

According to a sixth aspect, a flow channel cross-sectional area of the evaporation flow channel is smaller than a flow channel cross-sectional area of the supply flow channel.

Therefore, since the liquid surface of the liquid-phase refrigerant in the evaporation flow channel can be raised, the supply of the liquid-phase refrigerant to the evaporation flow channel can be increased.

According to a seventh aspect, the evaporation flow channel has a plurality of narrow flow channels having a flow channel cross-sectional area smaller than the flow channel cross-sectional area of the supply flow channel.

According to an eighth aspect, there is provided a thermosiphon that is applied to a moving body, includes a condenser which condenses a gas-phase refrigerant and discharges a liquid-phase refrigerant, and a plurality of coolers which evaporate the liquid-phase refrigerant from the condenser, and circulates the refrigerant between the condenser and the plurality of coolers, in which each of the plurality of coolers includes: a first flow channel forming member that provides a supply flow channel through which the liquid-phase refrigerant from the condenser flows; a second flow channel forming member that provides an evaporation flow channel which evaporates the liquid-phase refrigerant by a heat exchange between the liquid-phase refrigerant from the supply flow channel and an object to be cooled to generate the gas-phase refrigerant; and a third flow channel forming member that provides a discharge flow channel through which the gas-phase refrigerant from the evaporation flow channel flows toward the condenser, and the plurality of coolers are aligned in a traveling direction of the moving body, and the supply flow channels are connected in series with each other to cause the liquid-phase refrigerant to be sequentially supplied to the respective supply flow channels of the plurality of coolers.

Therefore, when the traveling direction of the moving body is inclined with respect to the horizontal direction, the cooler on one side in the traveling direction is positioned above the cooler on the other side in the traveling direction in the plurality of coolers. Therefore, the liquid-phase refrigerant can be satisfactorily supplied to the respective supply flow channels of the plurality of coolers.

According to a ninth aspect, the supply flow channels of the plurality of coolers are formed so as to extend in the traveling direction of the moving body.

According to a tenth aspect, there is provided the thermosiphon including a bypass flow channel forming member that provides a bypass flow channel; and an on-off valve that opens and closes the bypass flow channel, in which one of two coolers of the plurality of coolers located on a front side in the traveling direction is defined as a first cooler, the other of the two coolers located on a rear side of the first cooler in the traveling direction is defined as a second cooler, the first cooler has a first refrigerant inlet that allows the liquid-phase refrigerant to flow into the supply flow channel, the second cooler has a second refrigerant inlet that allows the liquid-phase refrigerant to flow into the supply flow channel, the bypass flow channel communicates between the first refrigerant inlet of the first cooler and the second refrigerant inlet of the second cooler to bypass the first cooler, when the plurality of coolers is in a specified posture, the on-off valve opens the bypass flow channel, a part of the liquid-phase refrigerant from the condenser is supplied to the supply flow channel of the first cooler through the first refrigerant inlet, and a part of the remaining liquid-phase refrigerant from the condenser other than the part of the liquid-phase refrigerant is supplied to the supply flow channel of the second cooler through the bypass flow channel, the on-off valve, and the second refrigerant inlet, and when the plurality of coolers are inclined with respect to the specified posture, the on-off valve closes the bypass flow channel, and the liquid-phase refrigerant from the condenser is supplied to the first refrigerant inlet, the supply flow channel of the first cooler, the second refrigerant inlet, and the supply flow channel of the second cooler in a stated order.

According to an eleventh aspect, the supply flow channel of each of the plurality of coolers is formed to extend in a direction intersecting with the traveling direction of the moving body.

According to a twelfth aspect, there is provided the thermosiphon including: a bypass flow channel forming member that provides a bypass flow channel; a communication flow channel forming member that provides a communication flow channel; and an on-off valve that opens and closes the bypass flow channel, in which one of two coolers of the plurality of coolers located on a front side in the traveling direction is defined as a first cooler, the other of the two coolers located on a rear side of the first cooler in the traveling direction is defined as a second cooler, the first cooler has a refrigerant inlet that allows the liquid-phase refrigerant to flow into the supply flow channel, and a refrigerant outlet that allows the liquid-phase refrigerant to be discharged from the supply flow channel, the second cooler has a first refrigerant inlet and a second refrigerant inlet which allow the liquid-phase refrigerant to flow into the supply flow channel, the communication flow channel communicates between the refrigerant outlet of the first cooler and the second refrigerant inlet of the second cooler to bypass the first cooler and the second cooler, the bypass flow channel communicates between the refrigerant inlet of the first cooler and the second refrigerant inlet of the second cooler to bypass the first cooler and the second cooler, when the plurality of coolers is in a specified posture, the on-off valve opens the bypass flow channel, a part of the liquid-phase refrigerant from the condenser is supplied to the supply flow channel of the first cooler through the refrigerant inlet, and a part of the remaining liquid-phase refrigerant from the condenser other than the part of the liquid-phase refrigerant is supplied to the supply flow channel of the second cooler through the bypass flow channel, and the on-off valve, and when the plurality of coolers are inclined with respect to the specified posture, the on-off valve closes the bypass flow channel, and the liquid-phase refrigerant from the condenser is supplied to the refrigerant inlet, the supply flow channel of the first cooler, the communication flow channel, and the supply flow channel of the second cooler in a stated order.

According to a thirteenth aspect, the evaporation flow channel of each of the plurality of coolers has a refrigerant inlet communicating with the supply flow channel, and the refrigerant inlet is located on the lower side of the center portion of the supply flow channel in the vertical direction.

According to a fourteenth aspect, the refrigerant inlet is disposed on the lower side of the supply flow channel.

According to a fifteenth aspect, each evaporation flow channel of the plurality of coolers has a refrigerant inlet communicating with the supply flow channel, each of the plurality of coolers is formed to be recessed downward from the supply flow channel, and each of the plurality of coolers has a liquid storage for storing the liquid-phase refrigerant from the supply flow channel, and the refrigerant inlet of each evaporation flow channel of the plurality of coolers communicates with the liquid storage of each of the plurality of coolers, and is located at the same height as or below the liquid surface of the liquid-phase refrigerant in each of the liquid storages of the plurality of coolers.

According to a sixteenth aspect, the thermosiphon includes: a determination unit that determines whether or not the plurality of coolers are inclined with respect to a specified posture; and a refrigerant increasing unit that, when the determination unit determines that the plurality of coolers are inclined with respect to the specified posture, increases the refrigerant amount of the liquid-phase refrigerant supplied from the condenser to the cooler as compared with the case where the determination unit determines that the coolers are not inclined with respect to the specified posture.

According to a seventeenth aspect, the flow channel cross-sectional area of the evaporation flow channel of each of the plurality of coolers is smaller than the flow channel cross-sectional area of the supply flow channel.

According to an eighteenth aspect, an evaporation flow channel of each of the plurality of coolers has a plurality of narrow flow channels having a flow channel cross-sectional area smaller than the flow channel cross-sectional area of the supply flow channel.

According to a nineteenth aspect, there is provided a thermosiphon that includes a condenser which condenses a gas-phase refrigerant and discharges a liquid-phase refrigerant, and a cooler which evaporates the liquid-phase refrigerant by a heat exchange between the liquid-phase refrigerant flowing in from the condenser and an object to be cooled, and circulates the refrigerant between the condenser and the cooler, the thermosiphon including: a determination unit that determines whether or not the cooler is inclined with respect to a specified posture; and a refrigerant increasing unit that, when the determination unit determines that the cooler is inclined with respect to the specified posture, increases the refrigerant amount of the liquid-phase refrigerant supplied from the condenser to the cooler as compared with the case where the determination unit determines that the cooler is not inclined with respect to the specified posture.

According to a twentieth aspect, the cooler includes: a first flow channel forming member that provides a supply flow channel through which the liquid-phase refrigerant from the condenser flows; a second flow channel forming member that provides an evaporation flow channel which includes a refrigerant inlet communicating with the supply flow channel, and evaporates the liquid-phase refrigerant by a heat exchange between the liquid-phase refrigerant flowing from the supply flow channel through the refrigerant inlet and an object to be cooled to generate the gas-phase refrigerant; and a third flow channel forming member that provides a discharge flow channel through which the gas-phase refrigerant from the evaporation flow channel flows toward the condenser.

According to a twenty-first aspect, the refrigerant inlet is located on the lower side of the center portion of the supply flow channel in the vertical direction.

According to a twenty-second aspect, the refrigerant inlet is located on the lower side of the supply flow channel.

According to a twenty-third aspect, the cooler includes one or more liquid storages (63 a) formed to be recessed downward from the supply flow channel and storing the liquid-phase refrigerant from the supply flow channel.

According to a twenty-fourth aspect, the refrigerant inlet communicates with the liquid storages and is located at the same height as a liquid surface of the liquid-phase refrigerant in the liquid storages or located below the liquid surface.

According to a twenty-fifth aspect, 25. the one or more liquid storages includes a plurality of liquid storages aligned in the refrigerant flow direction of the supply flow channel, the cooler provides a plurality of the evaporation flow channels aligned in a refrigerant flow direction of the supply flow channel, and each of the plurality of liquid storages communicates with a refrigerant inlet of a corresponding one of the plurality of evaporation flow channels.

According to a twenty-sixth aspect, the flow channel cross-sectional area of the evaporation flow channel is smaller than the flow channel cross-sectional area of the supply flow channel.

According to a twenty-seventh aspect, the evaporation flow channel has a plurality of narrow flow channels having a flow channel cross-sectional area smaller than the flow channel cross-sectional area of the supply flow channel. 

1. A thermosiphon applied to a moving body, comprising: a condenser condensing a gas-phase refrigerant and discharging a liquid-phase refrigerant; and a plurality of coolers that evaporate the liquid-phase refrigerant from the condenser, the refrigerant circulating between the condenser and the plurality of coolers, wherein each of the plurality of coolers includes: a first flow channel forming member that defines a supply flow channel through which the liquid-phase refrigerant from the condenser flows; a second flow channel forming member that defines a refrigerant inlet in communication with the supply flow channel, the second flow channel forming member extending upward from the refrigerant inlet to define an evaporation flow channel in which the liquid-phase refrigerant evaporates through heat exchange between an object to be cooled and the liquid-phase refrigerant flowing into the evaporation flow channel from the supply flow channel through the refrigerant inlet and generates the gas-phase refrigerant; and a third flow channel forming member that defines a discharge flow channel through which the gas-phase refrigerant from the evaporation flow channel flows toward the condenser, wherein the refrigerant inlet is located below a center portion of the supply flow channel in a vertical direction, and the plurality of coolers are arranged along a traveling direction of the moving body and the supply flow channel of each of the plurality of coolers is fluidly connected in series with each other so that the liquid-phase refrigerant is sequentially supplied to the supply flow channel of each of the plurality of coolers.
 2. The thermosiphon according to claim 1, wherein the refrigerant inlet is located below the supply flow channel.
 3. The thermosiphon according to claim 1, further comprising at least one liquid storage that is recessed downward from the supply flow channel to store the liquid-phase refrigerant from the supply flow channel.
 4. A thermosiphon applied to a moving body, comprising: a condenser condensing a gas-phase refrigerant and discharging a liquid-phase refrigerant; and a plurality of coolers that evaporate the liquid-phase refrigerant from the condenser, the refrigerant circulating between the condenser and the plurality of coolers, wherein each of the plurality of coolers includes: a first flow channel forming member that defines a supply flow channel through which the liquid-phase refrigerant from the condenser flows; a second flow channel forming member that defines a refrigerant inlet into which the liquid-phase refrigerant from the supply flow channel flows, the second flow channel forming member defining an evaporation flow channel in which the liquid-phase refrigerant evaporates through heat exchange between an object to be cooled and the liquid-phase refrigerant flowing into the evaporation flow channel through the refrigerant inlet and through which the gas-phase refrigerant flows toward the condenser; a third flow channel forming member that defines a discharge flow channel through which the gas-phase refrigerant from the evaporation flow channel flows toward the condenser, and at least one liquid storage that is recessed downward from the supply flow channel to store the liquid-phase refrigerant from the supply flow channel, wherein the refrigerant inlet is in communication with the at least one liquid storage, the refrigerant inlet is located at the same height as a liquid surface of the liquid-phase refrigerant in the at least one liquid storage or is located below the liquid surface, and the plurality of coolers are arranged along a traveling direction of the moving body and the supply flow channel of each of the plurality of coolers is fluidly connected in series with each other so that the liquid-phase refrigerant is sequentially supplied to the supply flow channel of each of the plurality of coolers.
 5. The thermosiphon according to claim 1, wherein the evaporation flow channel is a plurality of evaporation flow channels arranged along a refrigerant flow direction of the supply flow channel, the at least one liquid storage is a plurality of liquid storages arranged along the refrigerant flow direction of the supply flow channel, and each of the plurality of liquid storages is in communication with the refrigerant inlet of a corresponding one of the plurality of evaporation flow channels.
 6. The thermosiphon according to claim 1, wherein the evaporation flow channel has a flow channel cross-sectional area that is smaller than a flow channel cross-sectional area of the supply flow channel.
 7. The thermosiphon according to claim 1, wherein the evaporation flow channel includes a plurality of narrow flow channels, and each of the plurality of narrow flow channels has a flow channel cross-sectional area that is smaller than a flow channel cross-sectional area of the supply flow channel.
 8. A thermosiphon applied to a moving body, comprising: a condenser that condenses a gas-phase refrigerant and discharges a liquid-phase refrigerant, and a plurality of coolers that evaporate the liquid-phase refrigerant from the condenser, the refrigerant circulating between the condenser and the plurality of coolers, wherein each of the plurality of coolers includes: a first flow channel forming member that defines a supply flow channel through which the liquid-phase refrigerant from the condenser flows; a second flow channel forming member that defines an evaporation flow channel in which the liquid-phase refrigerant evaporates through heat exchange between an object to be cooled and the liquid-phase refrigerant from the supply flow channel and generates the gas-phase refrigerant; and a third flow channel forming member that defines a discharge flow channel through which the gas-phase refrigerant from the evaporation flow channel flows toward the condenser, and the plurality of coolers are arranged along a traveling direction of the moving body and the supply flow channel of each of the plurality of coolers is fluidly connected in series with each other so that the liquid-phase refrigerant is sequentially supplied to the supply flow channel of each of the plurality of coolers.
 9. The thermosiphon according to claim 8, wherein the supply flow channel of each of the plurality of coolers extends along the traveling direction of the moving body.
 10. The thermosiphon according to claim 8, further comprising: a bypass flow channel forming member that defines a bypass flow channel; and an on-off valve that selectively opens and closes the bypass flow channel, wherein one of two coolers among the plurality of coolers located in front of the other of the two coolers in the traveling direction is defined as a first cooler, the other of the two coolers located behind the first cooler in the traveling direction is defined as a second cooler, the first cooler has a first refrigerant inlet that allows the liquid-phase refrigerant to flow into the supply flow channel, the second cooler has a second refrigerant inlet that allows the liquid-phase refrigerant to flow into the supply flow channel, the bypass flow channel fluidly connects between the first refrigerant inlet of the first cooler and the second refrigerant inlet of the second cooler to bypass the first cooler, when the plurality of coolers are in a specified posture, the on-off valve opens the bypass flow channel so that a first portion of the liquid-phase refrigerant from the condenser is supplied to the supply flow channel of the first cooler through the first refrigerant inlet and a second portion of a remaining of the liquid-phase refrigerant from the condenser other than the second portion of the liquid-phase refrigerant is supplied to the supply flow channel of the second cooler through the bypass flow channel, the on-off valve, and the second refrigerant inlet, and when the plurality of coolers are in a posture angled with respect to the specified posture, the on-off valve closes the bypass flow channel so that the liquid-phase refrigerant from the condenser is supplied to the first refrigerant inlet, the supply flow channel of the first cooler, the second refrigerant inlet, and the supply flow channel of the second cooler in this order.
 11. The thermosiphon according to claim 8, wherein the supply flow channel of each of the plurality of coolers extends along a direction intersecting with the traveling direction of the moving body.
 12. The thermosiphon according to claim 8, further comprising: a bypass flow channel forming member that defines a bypass flow channel; a communication flow channel forming member that defines a communication flow channel; and an on-off valve that selectively opens and closes the bypass flow channel, wherein one of two coolers of the plurality of coolers located in front of the other of two coolers in the traveling direction is defined as a first cooler, the other of the two coolers located behind the first cooler in the traveling direction is defined as a second cooler, the first cooler has a refrigerant inlet that allows the liquid-phase refrigerant to flow into the supply flow channel and a refrigerant outlet that allows the liquid-phase refrigerant to be discharged from the supply flow channel, the second cooler has a first refrigerant inlet and a second refrigerant inlet both of which allow the liquid-phase refrigerant to flow into the supply flow channel, the communication flow channel fluidly connects between the refrigerant outlet of the first cooler and the second refrigerant inlet of the second cooler, the bypass flow channel fluidly connects between the refrigerant inlet of the first cooler and the second refrigerant inlet of the second cooler to bypass the first cooler and the second cooler, when the plurality of coolers are in a specified posture, the on-off valve opens the bypass flow channel so that a first portion of the liquid-phase refrigerant from the condenser is supplied to the supply flow channel of the first cooler through the refrigerant inlet and a second portion of a remaining of the liquid-phase refrigerant from the condenser other than the first portion of the liquid-phase refrigerant is supplied to the supply flow channel of the second cooler through the bypass flow channel and the on-off valve, and when the plurality of coolers are in a posture angled with respect to the specified posture, the on-off valve closes the bypass flow channel so that the liquid-phase refrigerant from the condenser is supplied to the refrigerant inlet, the supply flow channel of the first cooler, the communication flow path, and the supply flow channel of the second cooler in this order.
 13. The thermosiphon according to claim 8, wherein the evaporation flow channel of each of the plurality of coolers has a refrigerant inlet in communication with the supply flow channel, and the refrigerant inlet is located below a center portion of the supply flow channel in a vertical direction.
 14. The thermosiphon according to claim 13, wherein the refrigerant inlet is located below the supply flow channel.
 15. The thermosiphon according to claim 8, wherein the evaporation flow channel of each of the plurality of coolers has a refrigerant inlet in communication with the supply flow channel, each of the plurality of coolers has a liquid storage that is recessed downward from the supply flow channel and stores the liquid-phase refrigerant from the supply flow channel, and the refrigerant inlet of the evaporation flow path of each of the plurality of coolers is in communication with the liquid storage of each of the plurality of coolers, and the refrigerant inlet of the evaporation flow path of each of the plurality of coolers is located at the same height as a liquid surface of the liquid-phase refrigerant in the liquid storage of each of the plurality of coolers or is located below the liquid surface.
 16. The thermosiphon according to claim 8, further comprising a processor programmed to: determine whether the plurality of coolers are angled with respect to a specified posture; and upon determining that the plurality of coolers are in a posture angled with respect to the specified posture, increase a refrigerant amount of the liquid-phase refrigerant supplied from the condenser to the plurality of coolers as compared with when determining that the coolers are not in a posture angled with respect to the specified posture.
 17. The thermosiphon according to claim 8, wherein the evaporation flow channel of each of the plurality of coolers has a flow channel cross-sectional area that is smaller than a flow channel cross-sectional area of the supply flow channel.
 18. The thermosiphon according to claim 8, wherein the evaporation flow channel of each of the plurality of coolers has a plurality of narrow flow channels, and each of the plurality of narrow flow channels has a flow channel cross-sectional area smaller than the flow channel cross-sectional area of the supply flow channel.
 19. A thermosiphon comprising: a condenser that condenses a gas-phase refrigerant and discharges a liquid-phase refrigerant; a cooler that evaporates the liquid-phase refrigerant through heat exchange between an object to be cooled and the liquid-phase refrigerant flowing into the cooler from the condenser and discharges the gas-phase refrigerant to the condenser, the refrigerant circulating between the condenser and the cooler; and a processor that is programmed to: determine whether the cooler is angled with respect to a specified posture; and upon determining that the cooler is in a posture angled with respect to the specified posture, increase a refrigerant amount of the liquid-phase refrigerant supplied from the condenser to the cooler as compared with when determining that the cooler is not in a posture angled with respect to the specified posture.
 20. The thermosiphon according to claim 19, wherein the cooler comprises: a first flow channel forming member that defines a supply flow channel through which the liquid-phase refrigerant from the condenser flows; a second flow channel forming member that defines a refrigerant inlet in communication with the supply flow channel, the second flow channel forming member defining an evaporation flow channel in which the liquid-phase refrigerant evaporates through heat exchange between an object to be cooled and the liquid-phase refrigerant flowing into the evaporation flow channel from the supply flow channel through the refrigerant inlet and generates the gas-phase refrigerant; and a third flow channel forming member that defines a discharge flow channel through which the gas-phase refrigerant from the evaporation flow channel flows toward the condenser.
 21. The thermosiphon according to claim 20, wherein the refrigerant inlet is located below the center portion of the supply flow channel in the vertical direction.
 22. The thermosiphon according to claim 20, wherein the refrigerant inlet is located below the supply flow channel.
 23. The thermosiphon according to claim 20, wherein the cooler includes at least one liquid storage recessed downward from the supply flow channel and storing the liquid-phase refrigerant from the supply flow channel.
 24. The thermosiphon according to claim 23, wherein the refrigerant inlet is in communication with the at least one liquid storage, and the refrigerant inlet is located at the same height as a liquid surface of the liquid-phase refrigerant in the at least one liquid storage or is located below the liquid surface.
 25. The thermosiphon according to claim 20, wherein the at least one liquid storage includes a plurality of liquid storages arranged along the refrigerant flow direction of the supply flow channel, the cooler defines, as the evaporation flow channel, a plurality of evaporation flow channels arranged along a refrigerant flow direction of the supply flow channel, and each of the plurality of liquid storages is in communication with a refrigerant inlet of a corresponding one of the plurality of evaporation flow channels.
 26. The thermosiphon according to claim 20, wherein the evaporation flow channel has a flow channel cross-sectional area that is smaller than a flow channel cross-sectional area of the supply flow channel.
 27. The thermosiphon according to claim 20, wherein the evaporation flow channel has a plurality of narrow flow paths, and each of the plurality of narrow flow paths has a flow channel cross-sectional area smaller than a flow channel cross-sectional area of the supply flow channel. 